As long as stats you need to attack in are 16's you're probably OK.
As you illustrate in your question you can get four stats to 16, though that will preclude any addition of feats (which are quite important for some classes, like the fighter, but they get more abil score increases so that's ok).
So no, MAD classes aren't exactly a problem in 5e. They still might be difficult to play, but the worst you're going to be is 10% behind everyone else.
The big factor here isn't actually the ability score increases, it's the ability score cap that is (or solves?) the problem. Basically, in previous editions (at least 4th), you started with a primary ability score of 18-20, and took it up to 30. And you only got to raise two scores twice every level up. That meant if you needed to raise 3-4 scores, you were going to have to choose between raising your top ability score less OR your secondary one even less (spliting increases between your secondary and tertiary) OR having your tertiary score fall way behind.
in BD&D, there is only really one (maybe two) PC classes that even use 2 stats, obviously the martial/melee classes in the PHB do as well. And with everyone needing CON, that really to me makes these characters MAD at least in proportion to other 5e classes.
At this point, though, MAD isn't a bad thing. As you illustrate, with a standard starting array, and the right race, you can have attack quality stats in 4 scores with only 5 ability increases. That's not to say you want to do that. I think most folks would prefer to get at least their primary up to 20, and that means forfeiting at least one of those 16s and no chance at feats. 10% doesn't mean much on any single attack, but the cumulative effect on your DPR will show. You might not feel it but it will be there.
Feats are an interesting quandry with MAD as well. Basically, supporting a MAD build will preclude the use of feats unless you are playing a Fighter or Rogue. So you must weigh the opportunity cost of the feats you won't be taking because you are choosing to use more than 2 abilities.
Metagaming
First, lets kill the metagaming ad hominem: "Metagaming is any strategy, action or method used in a game which transcends a prescribed ruleset, uses external factors to affect the game, or goes beyond the supposed limits or environment set by the game. Another definition refers to the game universe outside of the game itself."
Optimising a combat-oriented character to be good at combat within the rules is not and never can be metagaming. You can't even mount a game universe argument that it is: a person who has devoted his life to being a wilderness warrior (aka a Ranger) is going to learn to be good at fighting or die!
Comparison
Hit Points
Your hit point edge is insignificant; an 11 hp advantage is, on average, 2 hits or 1-2 rounds more staying power in a combat (less if fighting multiple foes). When you consider that the Paladin has an ability to heal 15 hp with their Lay on Hands ability at the cost of an action, they effectively have more hp than you do. You do have a definite advantage if you are being hit by things like fireballs; on failed saves you are the only one left standing.
This is an edge but a small one.
Damage output
I will assume everyone has the same stat modifier on damage rolls.
If you are using your bow and choose to use a spell slot for Hunters Mark, you can do 3 + d8 (bow) + d6 (Hunters Mark) (avg 11) on the first hit and the same plus d8 (Colossus Slayer) (avg 15.5) on subsequent attacks. This is great if you are fighting a monster with lots of hit points; it is not so good against a dozen goblins since the first hit will drop them and your Colossus Slayer never kicks in.
Meanwhile the Paladin with a longsword and the dueling fighting style is doing 3 + 2 + d8 (longsword) + 2d8 (Divine Smite) (avg 18.5) (I haven't considered some of the really cool spells they have).
The Rogue is doing 3 + d8 (longbow) + 2d6 (sneak attack - a good rogue should almost always get this) (avg 14.5).
The Sorcerer has a plethora of options (Magic Missile, Burning Hands, and Cloud of Daggers spring to mind) or they can just fall back on a damaging cantrip for d10 (avg 5.5). If they are a gambler, Hold Person can end a combat with a single humanoid on one failed saving throw.
If the Bard wants to be handing out massive damage in combat then they chose the wrong class; that is not where their talents lie, they are an enabler - they enable others to do more damage.
The Ranger is not the best at handing out damage.
Overall, you are playing your character to his strengths; are the other players playing to theirs?
Pacing and Encounter structure
You say "I was typically able to go first in any combat due to high DEX, and dealt such insane damage that the guys going last did nothing".
I read "The encounters are underpowered".
Don't misunderstand me: it is the nature of RPG that the PCs will win (almost) every fight because they can only lose once. Most combats will be and should be cakewalks, they are there because combat is fun and they consume resources. That said, they shouldn't be so insignificant that they are over before the first round ends. A quick combat like this is great if the players have planned and executed a great ambush, its not great if it is just way underpowered.
If you have enough spells to use a spell in every combat then you are not having enough encounters between long rests. Burning through spell slots for a non-core spellcaster should be a tough decision: "Do I use it now or will I need it latter?" If you are not thinking this, at least briefly, all the time then your DM is being easy on you. Fights early in the day will usually be easy but this is due to everyone having lots of resources, as you burn through spell slots and hp the same encounter becomes much harder.
Also, the structure of encounters matters. 5 PCs on one monster is an easy fight (unless the monster's CR is extremely high for the party); the monster can only target 1 PC while copping damage from all 5. 5 PCs on 5 monsters is much harder; the tough PCs have to control the battlefield or the squishy PCs will get squished. 5 PCs on 15 monsters, even very weak monsters, is really hard; everyone is copping damage and the fight will last 4-5 rounds minimum.
Best Answer
I've DMed in a lot of different ways over the years, and I love building sandboxes, but often players get confused and lost if there are too many options. I've evolved a way of keeping the sandbox feel, which make the world feel real and evolving around the players, and keep my own sanity for preparation and the players not feeling overwhelmed, in a few simple ways:
I pepper the world with things that could be entry points for quests or adventures (plot coupons). The barmaid that looks troubled....that mysterious scroll you found in the last dungeon....the weird laws in the last town you entered...the goal being that all of these things are out there, but aren't things I'm actively pushing towards (see point 2). At any point the players could get curious about them, and spend time investigating them (and I'd be ready to roll down that pathway) but they won't pick up on most of them, and won't care about most of them.
Give the players options when they feel lost. I like to recap the last session by bookending it with their motivations. E.g. When we last played the party was investigating X. insert action recap here. So what do you want to do? Continue further into the dungeon to try to find X, or escort the prisoners you've found back to safety? Now, they can definitely do anything else and I'm not railroading them, I'm just reminding them of their options (and usually whatever they discussed last time to get the discussion going again). If it comes to a point where the party is just undecided and can't make up their mind (happens more with new players) I'll remind them of one of the many plot coupons they have picked up. (e.g. They are worried about fighting the dragon they know is ahead, so I remind them that they just picked up a strange dwarven sword, and the smith in the last town seemed to know a lot about runesmithing).
For your particular concerns with the business, I would make it a set piece that generates x money every week/month. Eventually the players will want it to generate more, in which case you tell them about ways to do it (quests). Alternatively, if you really want them to focus on their business, have them go to collect their money one day and find the windows smashed in or boareded up, and the workers scared because they had been robbed (or have the guard come and question the players because of the same).