This is all true (although not all old houses are poorly insulated -- the ~60 cm of thatch and wattle and daub construction also is surprisingly good at insulation. It even comes complete with Tudor-era built in biomass heating!).

I think a lot of the bad press that goes on about new builds in the UK at least at the moment are due to "chicken coop Barrett Homes", i.e. a large developer building the largest number of houses possible with the cheapest construction method. There are horror stories in the tabloid press of people buying houses from ~2000 that are starting to have major structural problems, or have other major flaws. The rooms are meaner in size and there is a lot of resentment about developers making ~£300k profit on each property (and building ~200 of them at a go).

Obviously, there's a massive selection / survival bias here. Bad homes are more likely to be demolished. Good homes are more likely to survive.