I would suggest a way to resolve this would be to put upper level users on a probation system where they have to gain a certain number of merit over the probation period to maintain their rank, otherwise they get demoted.
so old hands who are on vacation (or dead) during the "probation period" get demoted?
are we demoting hal finney from senior member? he's only received 26 merit.
you're basically erasing all contributions that people made to the forum between 2010 and 2017. the people that made this forum
great once. screw that. old hands shouldn't be penalized just because most new members are spammers.
The outline I made in OP isn't perfect, of course there are some flaws and I do not believe that all members should be held to the same standard, even though it would be seen as unfair. I think that certain, clearly well-known, informative and respected users could be immune to the system, this would likely have to be a manual upgrade and could be decided based on community votes.