Well that's what people asked for when they wanted more "depth" to the game mechanics so in we go with skill trees ?
Hence why I said "elements that are associated with the RPG genre". I also was very obviously talking about games from other genres that take elements associated with other genres, so not sure why you listed the last few genres since the entire point was that there's too much saturation of these kind of systems (I used the term "triple A game" but really it's a problem in gaming in general)
The issue isn't that games don't emulate RPGs close enough. It's just that the skill trees, or leveling systems, or whatever you want to call it, aren't very well implemented a lot of the time.
Anyways if people think that adding a skill tree automatically creates depth in game mechanics than I would say that is pretty ridiculous ... I guess on a mechanical level it technically is an added layer to the game but it definitely doesn't translate to depth when in game.