The protest itself won’t have any impact. Two days won’t be enough to alter a single thing. Those that are going to remain dark indefinitely I wouldn’t be surprised if they are taken back by Reddit and assigned another mod.
Corporate will win in the end, even if it does turn out to cost them.
Hopefully more subs will follow r/videos lead. They have planned to go offline indefinitely/permanently.
Although it's quite likly reddit admins will nuke the mod team and reopen it with new mods.
The attempts at indefinite blackouts could have more impact than we expect, even if admins intervene and reopen them with new mods. They're doing this very publicly and with overwhelming support from their communities, so the "takeovers" would just make it look even worse for Reddit.
That will not change Reddit's mind about their plans, but it could convince more users to move on to greener pastures (Lemmy or otherwise)