Hopefully many of these wind up staying private longer, 2 days isn't going to convince reddit admins of anything. The real shift will come when large subreddits start actively pushing their users to Lemmy or Mastodon or wherever else, nothing happens till users leave en masse.
It's likely - and is already being spoken about over at Reddit - that admins will just push out existing mods of the larger subs. I'm sure they'll find replacement mods. Or maybe just use bots.