Not the person you just spoke to, and I don’t have any skin in this game, but technically speaking we don’t know if it tripled because of him or despite him, right? The truth is likely somewhere in the middle, but who knows where exactly.
Or if another CEO could have done better. While Microsoft was a mature company at the time, it's still part of a very high growth industry. He was CEO for 14 years, so just tripling the revenue (and that's in nominal terms, not counting inflation) isn't exactly spectacular.
Okay but we do know it did triple under him which in general is pretty good.
If you take the time to listen to this excellent interview, you will definitely be able to form your own opinion.