Above you write: “ RNA can obviously enter the cell nucleus (that's RNA function). ”
but I believe this is not true.
Normally, mRNA is produced in the nucleus and then is transported out of the nucleus. It is then turned into protein by ribosomes, which reside outside the nucleus.
My understanding is that mRNA from mRNA vaccines is not thought to enter the cell nucleus—and certainly this is not necessary for their function.
I’m not sure the fibrosis due to COVID-19 is really the same thing as the article on Wikipedia you link to. Pulmonary fibrosis that arises with autoimmune cause, or no apparent cause, may be more likely to be progressive than that due to COVID-19.
Damage from COVID-19 could still be disabling, of course, even if not progressive.
See here where this matter is discussed: https://www.newswise.com/coronavirus/fibrosis-or-pulmonary-fibrosis-covid-19-coverage-leads-to-confusion/?article_id=730976
Regarding your premodern city size question---I don't see a real constraint emerging from transportation speed. Here's my reasoning using your figures: a city with N people needs N * 5000 sq. meters of land to supply it with food (assume the land can sustain production indefinitely). If this land is a disk around the city the furthest the food has to come is sqrt(N) * 40 meters. If the food is carried at 10 miles a day, the longest supply lines require transporting food for only ~2-3 days for a city of a million, or ~25 days for a city of a 100 million.
Of course this does not a lead to a clean limit because it seems to me there is no very simple limit on how long the food could travel before it is eaten... But especially the first of these (2-3 days) seems reasonable.
Now, as you note it is transportation cost that is key, not just speed. But this requires estimating many more numbers. What did your calculation / model look like?
This argument has made me start seriously reconsidering my generally positive view of cryonics. Does anyone have a convincing refutation?
The best I can come up with is that if resuscitation is likely to happen soon, we can predict the values of the society we'll wake up in, especially if recovery becomes possible before more potentially "value disrupting" technologies like uploading and AI are developed. But I don't find this too convincing.