The community leaders aren't just upset about the policy change, but also trying to avoid contending with managing their communities 100% with reddit's inferior first-party moderation tools. It would make sense for the time-gated protests to be followed by a longer tail of deterioriating quality as mods simply quit.
It looks like that's what the /r/music team is planning to do already. They'll be closing the sub indefinitely on June 12, and one of the mods has remarked in a sticky comment on the announcement thread that they've been paying "$5/month to run our own servers to do stuff that reddit can't for the past 7-8 years."
It's remarkable to imagine creating a platform where community members will be so passionate as to work for free and even spend hundreds of dollars of their own money to enable working for you for free. All the more remarkable to see Reddit treating said community this way.
[0]https://old.reddit.com/r/Music/comments/141tzgd/update_rmusi...