That's a good point.
However, the narrative of "blame the boomers" is a con.
Blow this off if you want, but just realize that unless you're a russian bot or an ally of the American oligarchs you're working against your own self interests.
The con is blame the problems of one group on another group to separate them and get them fighting each other. This distracts everyone from the real causes of the problems. It's the same as blaming the brown people, which is pretty popular right now too. (Not a coincidence: in both cases the groups have a hard time understanding each other and it's very easy to identify the other group.) Another big one is getting people to identify as Ds and Rs and letting them blame and fight each other. (They are somewhat harder to identify, but the red hats help.)
It's important for millennials to understand this because without addressing the actual problem you are not going to end up with an actual working solution.
You'll go after boomers and still see no improvements. No doubt the people benefitting from the con will say you simply need to go after them harder. Guess what? That other group of people aren't actually demons and anyone demonizing them is bs'ing you, whether wittingly or not.
That's not to say boomers haven't benefited from the current system -- they have (generally). But their main advantage there is that they vote. (I don't know the full solution to that, but one thing is we have to make voting easier.)
I think the main problem is the massive money in politics. The people with money have always used it to influence politics in order to get more money. But they seem to have basically won outright at this point, with firm control of congress and the supreme court. The executive is mostly under control. The guy at the top is a wild-card but can be managed and is incompetent in any case.
Anyway, I wish I had a lot of answers but I don't. Just keep your eyes open and don't fall for the con. That's probably not enough to ensure a good outcome, but if you don't it's enough to ensure a bad outcome.