I do wonder what country will be the first one to ‘break’ and implement restrictions on buying homes. The current situation is not sustainable, and soon something will need to give.
Governments should just build a bunch of socialized housing and rent it at a rent just high enough to offset the expenditure (i.e. way below private market value). That would put downward pressure on rents. That is what Vienna did and they are the only popular city in Europe without a serious housing crisis.
For my own part, I'm going to say that Vienna's approach has not actually solved the key supply problem.