It's almost as if half the people in this thread have never gone to see a movie before, otherwise it is weird for them to be so vehemently against paying for entertainment provided by someone else.
Gamers in general tend toward the stingy in my experience, preferring to purchase their books from Amazon and undercutting their FLGS *when they choose to pay for them at all*. It isn't just gamers of course -- lots of people torrent their entertainment rather than pay for it, sure of their entitlement to the labors of others because... some reason.
Now, if we are talking about your weekly game night with your friends, the exchange of money for GM time is probably not appropriate -- if for no other reason that you should not really mix business and friendship. But at a game store, is it really so far out there to expect a nominal fee that the GM then shares with the store. i run a lot of games at cons and I get "paid" with free badges and sometimes some room vouchers. Considering that without GMs there are no cons, this is appropriate (and maybe con GMs should get paid too).
Then there are premium services. i work with a GM collective that hires out for private home games and events. People with the means are willing to spend money on the forms of entertainment they like most. Why should TTRPGs be any different?
All that said, of course there should always be a free gaming option -- playing at home or school or the library or whatever, with a GM happy to run for free. Nor do I have a problem with a "GM Yelp" because if you are providing a service for which you ask money, people should be able to find out whether you are any good at it before hand.
