Re: that is simply not true though

I think you’re missing the point a little bit here, zn.

The OP’s larger point is that elite players are specialists. Not that they can’t play well at another position, but there is that one position at which they most excel, maybe even at an elite level.

Doctors specialize.

Attorneys specialize.

Accountants specialize.

Why wouldn’t professional OL players do the exact same thing?

Let’s don’t overthink this.