I mean when you really get right down to it, they all had jobs, which was of course, playing in the band. Why instead, did Shirley at least in one episode, insist that Keith get a "real job" if he wanted a car?

Wasn't Keith as it already was, going to school, recording/touring with the band, and acting as its song writer? In other words, wasn't Keith a big part of why they were earning that money with royalties, tour dates in Las Vegas, TV appearances, etc. in the first place?

So again, it couldn't have hardly been unreasonable for them to get a salary, especially the older ones such as Keith and Laurie and some bump in allowance for the younger ones.