Interesting question. I know that 90% of the time the bassist on the recording is going to be a better player
A you gain ecperience, that percentage drops. Also, you realize at some point that, in most cases, the bass player on the record has played the song a half a dozen to a dozen times, and then they hit record. If you're dong that song for a lot of gigs, you will eventually get to where you have played the song a lot more times than the bassist had when the recording was made. Now, you face the same issue that the original bassist does when the band tours - the song evolves, because the players figure out better ways of presenting the song - better parts, better arrangements, etc. Why is the liver version different than the studio version? Because the band has
learned what makes the song better.
I play church gigs. A lot of the tunes that we do are recorded with fairly simple parts - the artists know their songs will be played by players in a lot of cases aren't very proficient, so they intentionally dumb things down a bit. Sometimes more than a bit. Some of the churches I play in, the players are very proficient, often as good as or better than the folks on the record. We also are playing to a live audience, and what works for
that audience is not what's on the record. I play with a bunch of different worship leaders, and lots of vocalists. My job is to support what they're doing, and what's happening in the room - the part I play depends on what's happening around me. If I play the part on the record, it's never the ideal part for the situation I'm in. If I play the
same part for 3 different worship leaders, the part I'm playing is wrong at least 2 of those 3 times. It might be close sometimes, but most of the time, what I come up with is something that fits the situation better.