I have to correct you slightly here and point out that actually, a lot of bands hire very skilled session musicians to play on their albums. You know that expression "You get what you pay for?" Talent literally CAN be bought sometimes. And it is. Even "great" bassists are replaced in studio recordings by "greater" bassists. If you're a studio/session musician, it's a different world. Have a look at the credits of a few albums...the bassist in the band doesn't always play on the album.
Anyway, I'm not intending to nitpick, but I just wanted to point that out.
I would agree that many, if not most, SOLO artists hire session musicians, but bands?? I'd have to disagree with that, although I will admit that I don't usually check the album credits for bands.

