But in both cases they need landlords, right?

Until that exists, we need landlords. Right?

On the other hand, rented homes has lots of demand, and that is only possible if someone else owns it.

Landslords provides a service that people need. Although not all landlords does it well.

Here is in Denmark they are at 100%, because that’s our law. As far as I know (as a consumer), it works just fine.

All soda bottles and cans can be returned in (almost?) any store that sells them. When we buy, a small deposit is added. When we return the container, we get the deposit back.

The deposit is adjusted every now and then to keep it small enough to not significantly affect customers buying power, but big enough that most people want the money back.