On the Fireside Fedi interview with Jerry ( the admin of Infosec.Exchange Mastodon instance ) a scary truth was suddenly revealed ( on 34:11 ): Just to keep the instance up and running he needs to spend up to $5000 a month, pretty much out of his pocket. Donations to the instance barely cover any of that. And if he will ask people to pay to use it, they will, rightfully so, switch to a different instance.
I am not disagreeing, I just think these options are not mutually exclusive. We should try all of those that we can. And while I can not force schools and universities to implement their own Mastodon instance for their students, I can pay a little bit per month to support developers and service providers of the libre platforms out there.