If the means/medians are higher, the tails are also higher as well (usually).
Norm(μ=115, σ=15) distribution will have a much lower proportion of data points above 150 than Norm(μ=130, σ=15). Same argument for other realistic distributions. So if all I know about fields A and B is that B has a much lower mean than A, by default I'd also assume B has a much lower 99th percentile than A, and much lower percentage of people above some "genius" cutoff.
Again using the replication crisis as an example, you may have noticed the very wide (like, 1 sd or more) average IQ gap between students in most fields which turned out to have terrible replication rates and most fields which turned out to have fine replication rates.
This is rather weak evidence for your claim ("memeticity in a scientific field is mostly determined, not by the most competent researchers in the field, but instead by roughly-median researchers"), unless you additionally posit another mechanism like "fields with terrible replication rates have a higher standard deviation than fields without them" (why?).
Some people I know are much more pessimistic about the polls this cycle, due to herding. For example, nonresponse bias might just be massive for Trump voters (across demographic groups), so pollsters end up having to make a series of unprincipled choices with their thumbs on the scales.
There's also a comic series with explicitly this premise, unfortunately this is a major plot point so revealing it will be a spoiler:
Yeah this was my first thought halfway through. Way too many specific coincidences to be anything else.
My guess is that we wouldn't actually know with high confidence before (and likely even some time after) things-will-definitely-be-fine.
E.g. 3 months after safe ASI people might still be publishing their alignment takes.
There are also times where "foreign actors" (I assume by that term you mean actors interested in muddying the waters in general, not just literal foreign election interference) know that it's impossible to push a conversation towards their preferred 1)A or 5)B, at least among informed/educated voices, so they try to muddy the waters and push things towards 3). Climate change[1] and covid vaccines are two examples that comes to mind.
Though the correct answer for climate change is closer to 2) than 1)
Agreed, I was trying to succinctly convey something that I think is underrated, unfortunately going to miss some nuances.