Mix’s problem is ego all they have to say is we really want you but all we have is $100 he is gonna do the gig because they want him and it makes him feel good
To be fair, I think he has two problems. He wants to be in demand, and those requests feed the ego. But more importantly... he doesn't seem to have better client's calling.
Most of us give the advice to turn down the cheap stuff. But I know that I have faith to do that because I expect I'll get another quality call for most dates that I want to work. Mix clearly doesn't have that right now, which is why he ends up on these assistant gigs.