Living in Central Scotland, we are spoilt for choice of both clubs and sessions (not open mikes), some of which are weekly, some monthly. Sure there are some nights when the audience is thin on the ground, sometimes unexpectedly - "thought more of you would come out for XXX" - but as far as I know all the clubs I attend are not in danger of going under. I am treasurer of one very small one, which would possibly be hovering on the brink if it were not that we get the use of the back room of a pub for free, and only run 3 guest nights per year: people therefore pay a very small sum for attending the session nights in between, which helps to pay for the guests, and oh yes, we have a raffle!
Raffle income is important to clubs, tho' I agree it can go on too long in certain venues: one group I know just dispenses with all the "fun" and running about, and just publishes a very large print list of winning numbers for people to check on their way out. This gives us a lot more playing/singing time!
As for audiences having a say in who appears, most clubs I attend either ask for suggestions at their AGMs or have suggestions boxes in which you can post any ideas.