Also, there's a new government initiative to provide incentives and special financing for property owners (who rent their property) to bring the efficiency of all properties up to a decent minimum level by 2030 if they wish to be allowed to continue renting them out. I imagine there may be some exclusions for certain very old properties, especially historical/monumental ones. But regardless, it should have a big positive impact.
The stories sound like comedy: entire block of flats was built the wrong way round, someone moved into theyr flat and found the balcony was missing - the balcony door just led to a 30 meter drop. They forgot to lay cable down for internet, so a new block only has 8 megabit ADSL. The building I am in, they made the holes for fire sprinkles in the wrong place - so there is a hole in the ceiling, but nothing behind it. The sprinkler is 20 cm away from it, inside the ceiling, and if something goes wrong it won't actually be able to pop out
What I’m trying to say is that this is about incentives, not about how old things are. The modern building let their tenants cover the AC cost while the old one had water heating instead included.