What gold 4 tent said -Garen’s entirely predictable, and the simpler a champion’s kit is, the more predictable it becomes. He’s gonna run at you with Q... (if he’s a bit smarter, he’ll auto first and then Q for a reset).... Then he hits E.
Pantheon is another strong but mechanically basic champion. Point and click stun. Throws spears. Throws more spears. Ignited you. Throws another spear.
So while upfront you may think they’re stronger, but they do have a very real weakness which is a complete lack of innovation and utility.
As a jax main, I can tell you I’d much rather play against Garen and pantheon (my “counters”) than mechanically complex champions like Yasuo or riven (which I “counter). And if you can’t find ways to defeat completely predictable opponents, it’s not they who are the “brain dead” ones.