You don't understand. These apartments are shared (in most cases). Communal houses are a complete disaster if you don't choose who gets to live in there with you (theft, fights, -God forbid- rape, parties, bullying, ...)
This is a very good point that these discussions always ignore.
A friend of mine purchased a duplex house so she could live downstairs and rent out the upper floor by individual rooms. The only way she found that it worked was to have new tenants vetted by the existing ones. The 4 rooms were rented individually with shared kitchen and bathroom, but by letting the tenants have a say in who they shared the space with, turnover was very low and people tended to get along better.
