Audience is a good point.
No union could draw a crowd for you no matter what. You have to target your own audience. If you want to play current pop, rock, or whatever, you have to target that crowd. But are they going to go for what they consider a bunch of old fogies playing current rock or pop? Hell no. They want to hear their own generation just as you wanted to hear yours when you were younger. I'm not sure they really want to see a bunch of balding raisins holding guitars dancing around on a bandstand.
You have to target the audience in your age group that want to hear the music you play. For some it would be nursing homes.

For others it may be earlier rock. Mid 40's crowd. Kids aren't going to come and see you because they, for the most part, want to hear the music of their generation played by musicians of their generation. You can diversify, but by doing that you are not targeting anyone in particular. And that means lower gates and a smaller following. And for some age groups, the surviving following that actively participate in club music is fading.
This whole thing about unionizing sounds like scabs wanting higher wages buy letting some other band hire you after they fight to get the price and the venue. Not meant to be offensive, that is what it sounds like to me. One solution is to find your niche and an audience that YOU can draw and get to follow you. If you prove that you can consistently pack a house you can get a good price.
There is a band around here that I shall not name. They play for an older rock crowd and play the oldies that that crowd associates with. They are NOT that good. They get top dollar and have a great following. Their skill as musicians is far secondary to the selections they choose to play. They occasionally graft in new material of the day that they think will appeal to their target audience. They play just enough new stuff to keep a younger generation a wee bit interested, if and when they show up. but they are not their target audience. AND THEY HAVE TO TURN DOWN GIGS. And there is also a country band that has a huge following, but they are all top shelf musicians. Still they attract mostly people in their own age group, and they play what their crowd wants to hear.
If you want to be a whore, you have to act like a whore and play what they, not you like to play. You have to play what they heard when they were growing up to keep them around. If you want to have fun, play what you like to play. But don't expect to get great jobs. Few are going to pimp out 40-60 year old bands. Maybe if you are good enough the younger generation will catch on and keep you in mind when you are playing somewhere. But you can't count on them.
Neither a union nor a federal mandate can force people to come and see you. You can not force a club to hire you for whatever you think you are worth. Haven't you already discovered that you aren't worth much? I think that is what started this post in the first place. Prevost82 said it. Shoot for fairs and bigger venues. I do not think the younger audience is as dumbed down as you say. They are simply enjoying the music of their generation played as it is in their generation. It isn't any more moronic to them as Kiss or Elvis was to your parents generation. You aren't going to steal their generations music from them any more than your parents could steal yours. They said the same thing about Elvis after a generation of Sinatra. Glen Miller and the likes.
You have to do your footwork and research like any other business. Find your target audience. Learn to play what they want to hear. Find out how to get them to where you are playing. Advertise in a way that tweaks their interest, in places they will see or hear your advertising. In a nutshell, pimp your own damned self.
Hey dudes. we're older. Younger folks aren't interested in us. You have to be cute, have a tight ass, a cute haircut and all that crap. And a Justin Beiber haircut looks pretty damned stupid on a 60 year old.
Everyone sing along with Bobby.. Play music..... Be happy....