IMO, there's just not much to be done about it. My skills are about as good as they ever were, and my long experience can be extremely useful. Some employers will hire that and some won't.
I think the truth is, it really isn't a good fit. These places want young people because they want that kid to stay all night--maybe with a break with the gang for some beers before going back to work.
No thanks.
When a problem is rare enough, and people affected have other options, it is a reasonable pragmatic stance. Let the isolated business owner, who treats it as a personal social club, be less successful.
It is not good for society if these injustices proliferate. Economic imbalances result favoring arbitrary traits that don't increase the wealth of society. Innovation is inhibited, labor market inefficiencies result. People can't change careers as easily and adapt to technological progress.
But at an individual level, you have to play the cards you are dealt. There is a huge amount of noise in the system, but play them as well as you can.
Note that this is not the same as ageism. They'd be happy to hire me, even with my age, if they could pay me a bunch less.