If, you are correct that..
most users of Reddit are casual lurkers who just want a content feed and do not care about anything else.
And, a lot of the content creators and content moderators leave, decreasing the quality of the content on reddit.
Then, these lurkers will leave the platform.
I don't see why these folks would stay on reddit if the content decreases in quality. Especially, if we are assuming these lurkers do nothing to contribute to the content they are consuming.
It's interesting, you actually provided great evidence which counters your original claim that reddit will not be affected by all of this bad publicity.
One major point in the article is people on the fediverse shouldn't even play this "scaling game". You do well pointing out how trying to focus on scaling the fediverse is sort of a lose/lose situation. This is precisely why the fediverse shouldn't play this game because these social media corporations are masterminds at playing this game.
The major advantage the fediverse has over these social media companies is the fediverse doesn't need to play this game. Social media companies are slaves to their shareholders, meaning every decision they make ultimately needs to increase profits. For the fediverse, there are no shareholders that needs to be satisfied with higher profits. This is why the fediverse should just focus on shared values. Bring people into the fold of the fediverse because they are tired of the enshittification which ultimately affects all social media platforms owned by large corporations.