[astrange]

The only thing that matters is how many homes there are; stuff like this and vacancy taxes has barely any effect. The main reason to do it is if you want to appear to solve the problem without actually trying to solve it.

The main reason anyone would own two SFHs is that you need to do this in order to move. If you sell your first home before moving you're homeless. And after that it can take a long time to find a buyer.

They're a bad rental investment though because it's way too risky to own one; one bad renter or one roof replacement means you've lost money.

[Qwertious]

>The only thing that matters is how many homes there are

Cost of construction also matters - it reduces the renter's BATNA which reduces bargaining power.