It is true, there has been a shift in game design and in how the skills approach has been faced, but as in all things related to small, independent publishers (which, given how big companies tried to stay faithful to their brand, published the vast majority of RPGs), many have kept doing things as they were done 10 years before and many tried to innovate, leading to a very fragmented landscape.
Initially, there were no skills at all. I'm looking at you, D&D, the first large RPG being published. (D&D sure has been a trendsetter for a good part of the last 40 years. I will frequently name it in this answer because it's the game I'm most familiar with, but also because of its trendsetter attributes.)
Then AD&D second edition came, and one of the features of rogues was non-weapon proficiencies. The designers of D&D 3e didn't like this being limited to rogues and built the skill system that originated many other ones.
Anedoctically, I remember talking with a friend that only ever played D&D and Cyberpunk and his idea of making a new system involved lots of interlocking skills and attributes that tried to model realistic characters, like getting a penalty to agility for every five points in strength.
I've seen lots of D&D players lament how some abilities and some skills encompassed too many proficiencies. Maybe I am good at balancing on mud and slippery surfaces but not so much on the tightrope?
To me, this means that there was a perceived need to "fix" the faulty, approximate and existing ability/skill systems by refining them and by decoupling, and this led to a proliferation of skills, resulting in the systems you own.
On the other hand, some other designers felt the need to simplify the game, reducing the time spent looking for the right skill, at the expense of this perceived realism. Having read many forum posts about the paradigm shift from games where you have control over what your character tries to do and games where you have control over the story your character experiences (influencing things that your character can't influence), I think we are looking at a similar concept: elegance and focus of the game versus trying to turn the game into a reality simulator is a common conflict between game philosophies.
So, some games keep using lots of skills, because that's what the authors believe is good for realism, or because this granularity is something they enjoy.
Some games do not, they have more important things to do with their mechanics than trying to be a skillset simulator. But there was a certain point in time when this approach was not used (or at least it was not widespread, or it was used by niche games you didn't knoe yet), and then a point where a large and vocal community said that it was a bad approach.
To go back for a moment ta the 800 pund gorilla in the room, both D&D 4e and Pathfinder (two different evolutions of D&D 3e) reduced the number of their skills. We were at a point where, even with 8+Int skills per level, a rogue couldn't possibly buy all the skills that were needed to define the concept of "things any rogue should be good at". And this could very well be another reason why skills got reduced. 4e gave away with perform, craft and profession skills, that were of no use to adventurers. Again, the game gained focus and lost realism (or rather took those things out of the game, so that the players could be good at it without having to spend points there, subtracting to the more useful things).