I think Voat originated out of protest due to Reddit censorship. So a lot of the userbase existed out of people whose opinions or interests were censored on Reddit. In practice, this meant that Voat quickly became an alt-right board.

I’m sceptical. If most subs only protest for 2 days, then all Reddit has to do is weather the storm and then continue on. The only way I see it having any further impact is if many large subs black out indefinitely.

Reddit would either be forced to make concessions or escalate even further by removing the mods of the protesting subs and forcing it open again. That would be a further sign of bad faith and really piss off all these mods that spent up to a decade doing moderation for free.