Read it as "when they get older" if that makes you feel better. It's known that people are more likely to switch from liberal to conservatives when they get older than vice versa.
Except that is not happening with the current generations. The move from fiscal liberty to conservatism happened with previous generations because they accumulated assets like housing etc that they want to protect.
The current millenial/GenZ generations are dealing with multiple economic crises during their career development, as well as property and other asset bubbles keeping them from accumulating the same assets as their parents.
One could also say people get more conservative as their mental acuity decreases with age, but that too, would be an uncalled for judgement and projection of one's own political views.