Reddit got more important once it Google ranked higher and the astroturfs found out, that people trust a review on Reddit inside a thread more, than multi million dollar marketing scam action, trying to game Google algorithm or other sites. The same will sooner or later happen to the fediverse if it ever grows. It's unavoidable, sadly.
When they started counting all their bot accounts and banned accounts even though they have been replaced by new accounts.
Reminder that reddit recap has shown that even with minimal activity, you'll end up in the top 1% of reddit users for that year. That means at least 99% of reddit, are dead accounts.
What do you mean by "dead accounts"? On any given platform, there's a LOT of lurkers, and they count as active users because they're using the platform. Only a small portion of users comment, and an even smaller portion actually post content.