Property tax != land value tax. Properties in foreclosure may well have very low land value.

no, in the US at any rate property taxes are scaled exactly by land value. Usual scheme is 1% or so of assessed value, which is typically recalculated yearly. Some states have "homestead" exemptions where the first, say, $150,000 of value on a primary residence is exempt from tax. There are also (at least in California) special assessments for a fire or water district that are put on top of the yearly property tax, usually because of state laws that limit the rate at which assessed value can be increased or super-majority provisions for altering property tax rates, and so on.

Land value being the value of the land less the rebuild cost of any structures? That is the definition I was using. House prices are the wrong metric.

property taxes are virtually never the cause of foreclosure because every state law I've looked at (about 10) have long lead times before the government can sell the property at a tax sale to collect.

What happened in the last crash (2006 peak to 2009 trough) was a sharp decline in property values and reassessment at those lower values. So many / most homeowners did see their tax bills fall. (Exception would be in states like California which have Prop 13-like freezes on the ability of the state to increase the assessed value from year to year.)

The foreclosure problem was cause by values dropping and hence Loan-to-Value ratios going above 80%, which is about the highest it can go for a refinance loan. Couple that with the pick-a-payment / interest only loan terms and lots of folks were locked into loans that they couldn't get out of, only to find that exactly when unemployment hit their payment went way up.

The cities where property taxes matter in the US land is still much more valuable than how much it's getting taxed.