I agree with some of what you say, but I don't regard gigging as a "privilege". I'm experienced/good enough to be worthy of my place on the stage. Whether people like what I do is another matter, of course, but that's their choice. It doesn't alter the fact that I do what I do competently.
For much of my life, music has been a sideline that earns me extra money, although I have had a few periods during which it was my sole source of income. However, I wanted to be able to pay a mortgage, have a family, etc, so I kept a day job for the majority of the time.
I also made it clear above that I'm not opposed to turning out for charity, so it's not a case of saying no to charities and focusing on paid gigs. I make monthly donations to a few charities and am happy, provided the cause is one I have sympathy for, to turn out and play for free on occasion.
However, the fact that my band may be willing to give our time and effort does not entitle people to treat us without respect. Covering basic expenses (we're not talking 5 star hotel stays and expensive dinners) is part of that respect.