Realistically, there are a large amount of people who don't care about the protests. They're going to be creating content. I wouldn't be surprised if the people most outraged are the ones who don't even comment that often.
Otherwise wealth correlates somehow with both caring about your interests, and caring about abstract causes, for different reasons and often not in the same people. This is why 1) businesses catering to affluent people are often more cautious about the cheapest tactics (even if they ultimately go for the same results), 2) there is so much public faux political idealism from companies.
The biggest issue most vocal users (including many mods and developers of third party apps like Apollo) have, is that the prices are much higher then the expections reddit set beforehand and that everything was only communicated 30 days in advance.
If reddit wanted to keep third party apps, but have them pay for the users use of reddit, they could have implemented a transition plan. Or make it work another way. Or charge a realistic amount (you yourself state reddit's users are low value, but reddits is asking for $20 million per year in missed monetisation just for Apollo's users, which is very high value).
Instead, reddit seems to approach this aggressively, signalling through their actions that they intend to kill off all third party apps. That's what the the subs going dark are protesting against. Especially since reddit's own site and app are of significant lower quality.
So if ad revenue isn't going to do it. Then it needs to be a freemium model with subscriptions. They probably get 25% of their revenue from reddit premium. That also means, charging for the API.
The problem for many of the third party apps is they've also been running a freemium model with very low overheads due to the fact Reddit has been largely funding their freemium model. They've been charging next to nothing for their premium options ($1.50 a month) and they have massive amount of very active users. They're so big that paying a reasonable per API request fee results in a massive bill. A bill they can't pay due to a freemium model and super low fees that don't pay for the freemium users. Third party apps directly compete with Reddit, therefore it's fair they pay Reddit for the resources they use as well as the lost potential of the users they did take. Those paying for premium on an app would probably pay premium on Reddit.
Then comes in the low value users, who are outraged the free toy they have wants to make a profit. "It's too much money" - funny enough Reddit users think they're worthless - was one of the main cries. "This third party app IS REDDIT" - well if they're Reddit they shouldn't need Reddit access. A userbase who resists being monetised. Either they're monetisable or they're not. If they're not the company can't survive. What the Reddit users need/want is a non-profit.