I am allergic to overly simplified brilliant ideas: the notion that age directly dictates document verification behavior is a perfect example of media hype.
It's not age that is the key variable, but rather responsibilities and practical constraints.
A 30-year-old parent with children will manage passports months in advance, whereas a single septuagenarian without such responsibilities might be less vigilant.
The true drivers are mental load and the concrete consequences of forgetting, not a birth date.
A missed flight due to a missing document costs a lot, and it's this real cash lost that motivates preparation.