I don't believe this is going to be the case currently... the trend towards conservative was a fiscal phenomenon, as young kids who didn't have a lot of money and wanted a welfare state grew up and became financially independent, they wanted to keep what they were working to get. This would cause a self centric migration from trending democrat to trending republican.
That isn't how the partisan tribes currently work... They've become more of a "morality" enterprise, on both sides.
The choice is now if you think it's appropriate to ban huck finn and Tom Sawyer for the n word, or ban homosexual references. It's a question of do we spend taxes on blacks and the poor, or do we spend it on cluster bombs for Ukraine.
I don't think people will evolve from one side to the other the way boomers did. I think they're evolving farther from center, on both sides.
I don't like book bans period. I don't like the budget growing exponentially period. I don't like that 99% of the population increasingly wants the other half to be completely discounted... I'm essentially evolving towards not liking anybody at all.
I don't think "liberals" are going to become more "conservative" as they age, because that scale is divorced from party politics. Liberal is no longer a democrat trait, and conservative isn't purely republican. Both have adopted the entire con/lib scale in their own way. Democrats have conservative values, republicans have liberal values (the latter to a far greater degree, but I don't think it matters tbh). Just depends on what issue you're talking about.