So energy efficiency is paramount.
So why are these doors, even the modern ones, just a few inches thick? I'd expect to see the doors being 6 inch thick foam, and every outdoor door to be a double door (ie. into an entrance room, and another door into the rest of the building, such that only one door is ever open at once, to prevent heat loss).
I'd expect all the walls to be 12 inches thick (with 10 inches of foam) too - and again, this doesn't seem to be the case.