I understand that prevention is better than cure but sometimes the game gets a little late and when I'm in this situation it's very hard to counter as Protoss. The picture below almost makes his ground troops invincible as if he typed power overwhelming.
How do you usually counter this?
Edit: Thanks to all of you, I am able to finally counter it using mass Zealot + Colossi :
Best Answer
As a Protoss, you need to focus on a few objectives when fighting against bio Terran:
Some things you need to be doing:
Keep up with upgrades. I can't stress this strongly enough. Maxed out vs. maxed out, Terran will probably win in the majority of the cases unless you have some aces up your sleeve (more on this later). Get that double Forge and chrono-boost the hell out of the Gateway unit upgrades.
Good positioning is key. Large open spaces favour Terran as they allow them to develop that sick concave that will roll you over and prevent you from getting the most out of your splash damage. Cramped spaces, chokes and ramps are in your advantage, use them early on to deny them a good battle position, or just to stay alive. Early-game sentries are a must for crowd control, but don't invest too much in them after this, there are better things to spend your gas on.
Only one botched battle is enough to lose the game if your high-tier units die, so don't get caught out of position, and don't overextend to pokes and baits. An eager-to-kill Protoss is a dead Protoss.
Get some splash damage. You absolutely need this. No amount of zealots and stalkers will help against stimmed Terran army if you can't kill them quickly enough. Your first choice should be Colossi -- the Terran probably won't be producing Vikings just yet, and be getting Medivacs instead. Getting a critical mass of 5-6 Colossi (with sufficient Zealot meat shield and some stalkers to take down the Medivacs) should allow you to crush them in an engagement. Which leads us to...
Force tech switches. The bread and butter of PvT, IMO. After winning the first engagement with your Colossi, your opponent should start getting Vikings (otherwise they are pretty much dead if most of your Colossi have survived). Which is exactly the time you should be getting High Templars (Psionic Storm works wonders on a group of Vikings clustered up for sniping a Colossus), and ramp up your Stalker count. You'll likely lose all your Colossi at one point, but if you managed to make your opponent overcommit to Vikings, you should not be replenishing them. Instead, gradually add more Archons to the mix, especially if/when they start making Ghosts to counter your Templars. During the entire game, you should be the one telling them what and when to build, and prepare accordingly.
Shut down any drops. If you play defensively, the Terran will naturally try to do drops. Just one or two successful drops on their side can decide the victory in their favour, so keep on your toes. Get quick Blink, scout with pylons and observers, and patrol around your assets.
Keep your minerals low. You are very gas-dependent as a Protoss, especially when you are building Colossi and Templars. You'd probably have some minerals to spare, which you should invest in production facilities and zealots. Zealots with good upgrades and charge will buy enough time for your heavy hitters to melt their squishies, and will prevent them from reaching your high-value units. If you have a lot of minerals stashed, you are at a higher risk to die due to a timing push from the Terran before you have built an army composition that can crush them.
Some other exotic things:
PvT is all about quick upgrades, tech switches, and strategically planned engagements. You need to be controlling the flow of the battle in order to be the last to
gg
in the end.