Stanley Clarke said in an interview that he quickly realized that he only needed 20% of his skills for most of his work. Of course, that was when he was a jobbing bassist and before Chick Corea, Return to Forever, and all those TV/Film Scoring gigs. I'm sure those are more challenging.
I'm certainly "over qualified" for most gigs I do. I was Jack Bruce in a Cream tribute gig Saturday night and while the bass was no problem, I'm glad I could relax on it while I attempted to sing and cover Jack's vocal range while playing (now that was the challenge!). Yesterday, I did a TV taping and read Nashville Number Charts. The idea was to come up with a great part that locked in with the band (which included a former Elton John sideman, a top call session guitarist and the leader who owns a Jingle House and Studio in Nashville and has worked with The Everly Brothers, Dr. Hook, and any number of Nashville Acts). I didn't need any extreme Bass Athletics for this, but knowing how to come up with a tasty fill as I went from the 6b to the 5 chord by knowing the key I was in and doing it in 15 seconds or less with a good feel didn't hurt. The more you can widen your Comfort Zone playing, the better. It certainly helps your "feel" when you're not blindly stabbing at notes in the dark or worrying about where to go next.
Again, the OP was asking about Pros and Semipros. It sounds like a good topic for a Poll, if someone wants to put one up. I'm curious, too.