I beg to differ.
I teach bass at a couple of Community Colleges, and I have seen MANY students switch to double bass from electric. They quickly find out that they can make money playing out, so they dash off into playing some gigs, get tendinitis or carpal tunnel problems, then have to take a year off.
And these are guys I have warned repeatedly about getting in shape first.
Playing jazz walking bass is very physically demanding. You have to play every quarter note of every tune, and you can never stop. Tendinitis forces you to STOP playing, and you lose all that time you have built up.
I agree that playing a gig is a challenge.
Just make sure you are up for it, please. . .