It's not even necessarily a Europe thing. Or Asian. Though yes there are these tendencies. Italians, even in the US (North America actually) from my experience tend to stick together as a family unit for a long time. There's a lot of pressure on the young folks as well in some cases I know. Every situation is different in its own subtle way but I can definitely see how necessity (money) has made it so that kids stay with their parents until they're married. Catholicism will play a role too. Seeing that in many Spanish friends as well. Both the money and religious aspects. Germans too. I have a good childhood friend (yep I grew up there) who was always very close to his mum and built his house right next to his parents house for money reasons (free land so more money for the house). They are just constantly fighting over this or that. His SO really hates it now. I never understood why they did that. Sure, be in the same city, maybe even same neighborhood but right next to the parents especially after marriage? You're crazy! Same household? Way beyond crazy!

Personally I have healthy 6000km between myself and the parents. To be honest something like the 300km we had a some point is nicer and for taking care if the kids from time to time something like a few kilometers is best but same houseld is just stupid and I have yet to meet someone (even Asians) that will willingly do that for longer than necessary if they can help it. If they do it, it's for one of the reasons stated above like a Vietnamese colleague who did move back in with her mum for like a half year while trying to find a new place. They're close but same household is just way too close.