Random thought. What if we taxed property based on the area per person of the property, as opposed to sale value?

Edit and quick intro to those who mostly rent: most real property in the US, especially residential property, is taxed yearly based on some variation of something called "fair market value," usually assessed by a local tax assessor's office

I'm proposing that a property would be taxed for every square meter of space per person in the designated property unit. It can't be totally simplified, but should be fairly straightforward. There could also be progressive brackets. It might not make make sense to apply it strictly per person, but rather for a typical use. That is, we would assume "single family residential" properties to house 3.4 (totally made up number) people per house and property.

The goal of this is to find a fair, market-driven incentive to build density into urban cores.

A similar approach could be applied to commercial space (but probably not industrial).

It could be coupled with a sales tax (currently missing in most real property tax regimes, at least in the US) to capture runaway property valuations in certain jurisdictions.

Alternatively, we could drop the property value based tax rate (but not eliminate it), and then add a per person-area surcharge.

It's not meant to increase revenue, although it could certainly be used that way. It could also be use to decrease revenue, and maybe that would be a good way to sell it. But at the end of the day, developers and residents would both have an incentive to pursue as dense development as possible, even if there is not a density driving pressure of desirablity, which only exists in a few really cool urban cores.

Fair warning, I'm a dummy trying to talk about stuff I don't fully understand, but I wanted to see others' thoughts on this.

In the 1960s, America's GDP (per capita) was $3,000.
Also, in 1960, the federal poverty limit was $3,000 for a family of four.

In 2023, the GDP (per capita) was $82,034.
The federal poverty limit for a family of four in 2023 was $30,000.

This can't be good for the American people. Unless I'm drawing comparisons between two completely unrelated things?

People who are barely in poverty today would have to earn ~2.7x the amount they earn to stay consistent with those who were barely in poverty in the 1960s if GDP and FPL were still equal to each other. So what about the families caught in the middle? Too high earnings to get help and too low to thrive? They just suffer, I guess.

Out of curiosity, I calculated what the thresholds would be if the percentages of GDP to FPL were swapped between 2023 and 1960.

1960s numbers adjusted if FPL matched 2023's percentage:
GDP=$3,000
FPL=$1,111

1960s numbers adjusted if GDP matched the percentage comparison of 2023:
GDP=$8,100
FPL=$3,000

Please let me know if it actually matters that the GDP per capita is 2.7x the federal poverty limit for a family of four. Also, let me know your thoughts.