I don't think that your wealth is his issue. By now, you should know which basses work with your band. If you don't have a dedicated soundman, then i'd suggest only using one bass. If the guy is making comments to you and to the other bandmates, I'd take that seriously. If he has to set up his own gear, and run sound, then he's got a lot of work to do before each show. It's more important to have all members cool headed at the beginning of the show than it is to have a new flavor of the week bass. Do what it takes to make the band work as a whole.