Cork insulation would usually be skimmed over with plaster. You could have a look at insulatiing plaster too, but I think that needs to be thicker than cork to work well. Less munchable by critters though.
In an old building, you need to use breathable insulation, breathable plaster, and breathable paint (and breathable mortar, if you're repointing the outside). The moisture needs an escape route.
The criticisms of these polls is broadly correct. But I'm not sure I agree with the conclusion.
Nate Silver was bitterly attacked for weeks before the 2016 election for giving Trump a 20% chance of winning when most other (mainstream) pundits were giving him ~1%. It was bizarre to watch; they might as well have straight up told people not to bother voting.
It was Dem complacency that lost that election and thinkpieces like this do little but encourage more complacency. Trump fans will turn out. Biden-haters will turn out. People who would otherwise be holding their nose and voting for Biden will only turn out if they believe it matters. As they would have in 2016 if they'd known Trump had a realistic chance of winning.
Dems should be thanking biased Republican pollsters because Biden will only win this if a big chunk of eligible voters realise that they're going to have to hold their nose and vote for him.