As far as the protests go, they were quite successful. Reddit’s traffic went massively down; users, especially power users who uploaded content and moderated subreddits, left the site; and Lemmy became a viable alternative to Reddit with the influx of users. Reddit is still struggling to replace the moderators who quit, and they’ve been forced to take desperate actions like reinstating r/place and paying users who get a lot of upvotes to keep traffic on the site. The decision was never going to be reversed, the old free API scheme legitimately cost Reddit money and forcing users to use the official app like every other major social media has meant they could collect more data on users to sell. But as far as what the protest accomplished besides reversing the decision, it massively hurt Reddit and bolstered Lemmy into being a viable replacement