We could easily build more high density. There are a lot of young people who are interested in high quality high density housing - but it's just not available. Not everyone wants or needs a SFH. We don't build up in this country almost at all and that would solve a lot of the pressure. (It would also allow for people to use other means of transport that they actually prefer - many young people don't want to drive!)

There are a ton of people who are interested in living in densely populated big cities but the issue is that there isn't enough high rises or tall residential buildings to offset the demand.

There's definitely policy that could be done but it'd destroy the existing value for homeowners and landlords. That's why it doesn't get passed - obviously.