I think having some insulation is better than having none. But yeah, if you want to do it properly, it would cost a lot more.
As for heating your neighbours, a lot of cities have city heating and is paid depending on how many people live in the apartment, so you don't care that much about it. Of course, some folks have gas boilers in their apartment (like me) but it won't make sense financially to insulate the inner walls.
I think it's the same for new buildings here too, if not worse. A lot of regulations aren't actually respected and because a lot of builders left for WE, there's a huge problem with finding skilled workers.
As for heating your neighbours, a lot of cities have city heating and is paid depending on how many people live in the apartment, so you don't care that much about it. Of course, some folks have gas boilers in their apartment (like me) but it won't make sense financially to insulate the inner walls.
I think it's the same for new buildings here too, if not worse. A lot of regulations aren't actually respected and because a lot of builders left for WE, there's a huge problem with finding skilled workers.