I think this issue is tied to the “close the shidduch gap” (I hope I don’t get slammed by the Mods as a topic hijacker!)
My boys will enter the shidduch market at 22-23, same as all their peers, but with a strong work ethic, and NO assurances from their parents that all their needs will be magically provided. Will we provide a decent wedding and running head start? Of course. But by the time they make the first phone call, they will have a rough idea of what is expected of them within the first year or two.. and a game plan of how they expect to achieve that goal.
Dating someone closer to their age should hopefully provide them with someone who (as Azi pointed out) shares this goal, and understands / appreciates what it takes to make it happen.