Honestly don’t think it’s an insane idea. Not sure how effective $1 would be against bots, but I wouldn’t be surprised if the idea makes sense: basic and low friction to deter a large amount of spam. Maybe it’s $5 a year or whatever.
Of course there’s an equity issue for those who can’t afford this, especially if it goes mainstream and every online thing requires similar and we get Netflix -> Cable all over again.
But here on the Fedi I can see the idea working if applied to some instances that have set up the governance (eg co-op) and services (committed moderators) for it to make sense.
I think it would be cool if being an admin and moderator could genuinely be a side hustle or more without sucking away at someone’s passion.