If the intent was for everyone to use the same build, then game designers would not invest in the concept of builds. The convergence is clearly not intentional (it is a flaw in the game design) but also basically impossible to avoid in the presence of 1) high-dimensionality balance space and 2) highly-motivated meta-seekers.

I'm not saying people who do this are evil or bad. I'm saying they make games not fun, and it's not clear at all that this is solvable by the game designers except by vastly simplifying the games (e.g. getting rid of builds).

The fact they design for variance so much but then do not achieve variance is an empirical proof that it is a flaw in the design.

Yes, this is also a flaw with chess and is why chess is an extremely boring game. You can just ask someone their Elo and know who will win. As you get into higher Elos, variation in play style becomes less relevant, i.e. more homogenous. This makes the game boring.

It's not my job to lend airtime to other people's opinions on the matter. I'm sharing my opinion. You can share yours if you want.