Games nowadays are less competitive than they used to be, see the simplification of controls in RTS and simplification of shooter mechanics (i.e. no quake) etcetc
Just to point out, these two statements are unrelated. You can have a game with a low skill ceiling which nevertheless involves skills that take forever to learn. If those skills have a small impact on the outcome of the game, they won't raise the skill ceiling much.
The paradigmatic example of such a game is "chess dice", in which two players first play a game of chess, and then each roll a six-sided die. High roll wins; the winner of the chess game adds one to their die roll.
This game involves exactly as much skill as chess, while having a much lower skill ceiling than chess does.
Simple games can be very competitive because the best players can become much better at them. Chess and Go are good examples.
I don't love Fortnite, but building structures while shooting requires pretty demanding execution. "Simple" isn't the term I'd use at all.
Does it get any simpler than UT with instagib?