RPGMemes

It really depends.

I'm thinking about 3.5 in particular, where an optimized wizard will be able to do the job of the rest of the party (assuming they're built to be fine, but not power-gaming), better than them.

There's no real in-world way to balance that. Either the DM Fiats the power-gamer weaker, the DM tells the power gamer "no", or the rest of the party power games to. Its just too unbalanced.

If we're talking 5e, that's all out the window then. If 3.5's power runs from 0-10, the strongest 5e build is like a 6, and the weakest is like a 3. Its still extra work for the DM to balance, but can be done all in-world without needing to rely on metagame fiat.

And, of course, there's lots of other systems out there, where the above can be more true or less true depending on what kind of game it is, though 3.5's power ceiling is probably higher than 95% of the systems out there.