Why should MIT have to pay for someone else's historical mistakes? The IP addresses are just as valuable as any other part of MIT's endowment, and universities don't typically give their assets away for no reason. (If someone wants MIT to change to a /16, I'm sure there's some sum of money that could convince them.)

Ultimately, even if everyone gave their IPv4 addresses back, there would still be a tiny supply of addresses that can't scale. So we need IPv6 regardless of who is greedy about their IPv4 space.