Hit the nail on the head. It has been like this forever. But when they nerf the top performers, the sweatlords simply move on to the next best thing. It's an endless game of whack-a-mole.
So why do they do that? Why don't they just buff the weak builds? I think it's because it's much easier to nerf 1 or 2 things than buff 10 things. It boils down to laziness, I'm sure.
When they nerf something, they nerf it HARD too. And so it becomes a weak legendary RE. No longer a "top performer problem", but rather one of the many useless REs.
Do they play their own game? I doubt it.