Of course everyone understands this. The point is that the Dems won't lose many established voters if they appeal to issues that matter to young people (and all of us in fact). But they are missing the opportunity to establish brand loyalty among the 4+ million who join the electorate every year.

In the abstract, agreed. However, big shifts in their belief system don’t occur overnight. They’re established by certain groups (me, a 33-year-old millennial) continually voting for them for them to take an interest in my values as opposed to a 60-year-old former union autoworker in Youngstown