As for "power and flexibility" i'd add "self determination" and self determination is for better or worse.

I'd tell a 5 year old that the portal doesn't mean that the player is necessarily going to end up in a superior program or position on a new team. It does mean, however, that the decision is the player's to make, and not the school's. This is like free agency and baseball back in the 70s. The "power" (i.e., determinism) has shifted from the school/team to the individual. That's not always a bad thing, as good teams and good cultures, over time, will benefit far more than bad ones as their culture becomes in demand by the players.