Countable vs Uncountable Nouns – Is ‘Morning’ Countable or Uncountable?

Note that you can't use 'a' with an uncountable noun - 'a' means, and is even originally derived from 'one'. Also, most of the uncountable nouns you mention have countable synonyms: you could replace 'software' with 'program', 'advice' with 'recommendation'.

As for your last question - language is always in fluctuation, so we'll never be able to tell whether that would be the case.

Substances like sugar, milk, juice ,tea and coffee, etc are considered to be non-countable because you can't count them, hence the name. However, in different situations these nouns become countable.

E.g. I ordered three coffees.= you can count the coffee cups.

E.g. Can you pass the teas over here please.= the speaker is referring to three cups of tea which he cant reach.

Sometimes when we talk about different types of things (which are normally considered to be non-countable) then we can make them plural (countable).

E.g. There are many types of cereals on the shelf.

Often when we place things like juice, coffee ,etc. into containers then we treat them as single self-contained things which can be counted and therefore become plural.