I think even 100% reversal and going back to a free API indefinitely would still not be enough to get many of us back, including myself. The entire company has lost any remaining trust, and they were pretty much in negative balance to begin with.
The API stuff may have been the motivator, but this kind of movement doesn't happen so quickly without lots of underlying, pre-existing problems.
The protest had an end date because it shows that we're reasonable and willing to come back to the table. Now that Reddit has doubled-down, the next stage is to extend the timeline and magnitude of the protest.
The big apps and some of the bigger subs were always going to be going away indefinitely, while others will likely stay dark or even join the protest after staying out initially. Some will go back to normal, too, of course, just like some subs didn't participate at all in the first place.