I think in an originals "make it big" situation, the only musical talent you need to possess is being able to confidently play your songs each night.
The other talents you'll need are much wider and far reaching (as Blue has touched upon), and not limited to, critical thinking, PR, marketing, accounting, graphic design, tutoring, good business sense, web design and probably a whole lot more.
Obviously you can be a perfectly good, nay great! bar band and just focus on being an awesome bassist, but I strongly believe that the instrument is just one skill you'll need on your journey toward Originals Stardom.
As for passion, you'll definitely need some of that, if not for the bass then for the project in general. Remember, a lot of the legendary players are so because they did things 'wrong' and developed their own style. Not a bad idea to do the same!
Apologies for the long reply, great topic Blue.