Canada

I see where you're coming from, but I can't really see how that outcome would be any more or less common than it would be currently. I suppose I should've said effectively no tax, as it would simply be the new combined income being higher than the total property tax.

Some quick hypothetical math:

For illustrative purposes we can pretend every house is worth the same amount so we can deal simply with averages. At the same time we'll round the average household to 2.5 people. Let's say every house currently pays $5000/yr in property tax and that gets doubled, then we distribute the total evenly between every person in the country. We should end up with every individual person getting $2000/yr. If your household is 2 people, you'd effectively pay $6000, if your household is 5, you'd pay $0.

In the real world values obviously differ, but it would theoretically lower taxes on full houses and raise taxes on underutilized houses, with the impacts felt much less on small single occupancy houses and much more on huge mansions occupied by a small family.

I'm no expert, I'm simply a normal guy taking someone else's commented idea and running with it, so I'm sure there would be issues. In fact I see one already. This sort of sounds like how the carbon tax was supposed to work, where the average consumer breaks even, but in reality people in more rural areas felt like they were being punished because they didn't have realistic options to cut down on their fuel usage. This housing idea would have a similar issue where people in the least affordable cities would feel punished, because their shoebox sized studio might cost as much as a house fit for a multi generational family in a different province.