I don’t think a lot of people realize how college hockey has shifted regarding the age of players. Rather than being largely 18-21-year-olds, the ages have shifted and there are many more 21+ year old players coming in as “freshmen” to do their 1-2 years in college as a sort of “finishing school”
Don Lucia actually tried to make this a rule his last season as Gophers head coach. It would have prohibited any freshman over the age of 20 to play college hockey. Of course a couple other coaches from the Big Ten were on his side like Red Berenson and Tony Granato, but the rest of D1 hockey was against it and ultimately, it did not go through.
That is a big reason why the Big Ten has not been the league they thought it would since formation. They recruit the younger, NHL draft picks. The other schools like Mankatos, Duluths, and many of the NCHC schools recruit older, more developed players. Older players are generally better at playing defense and stick around longer. Plus a 24 year old is probably significantly more physically built than a 19 year old too. Its pretty rare to find a player that can make the jump directly from HS to D1 nowadays. There’s maybe 1 or 2 on a roster whereas years ago half the team was made up that way.
Right now, the route to success is to recruit older, more developed players that will stick around for a few seasons. If it was the other way around, Michigan would not have lost a game all season because they are the all-star version of a college team.