Most of those property taxes will be on parcels that will cost more to liquidate than the tax bill. We see it everywhere. I even have one. Its a residential lot that can’t be built on due to zoning so I bought it for $1000 and it has $3000 of tax liens. If the property gets rezoned it will be worth $50-100,000. If not $0. There are millions of those around the country and no more prevalent than in NYC where little strips and clips and odds and ends are all over the place.
in colorado, many unpaid tax liens are on worthless mining claims and mountain shacks ... just for grins, one time i looked at the list of properties in my county that one could obtain title to simply by paying the unpaid taxes ... a total joke ...