The people who don't pay their property taxes

Boston does follow that procedure. One need only need go to the registry of deeds where these things are filed.

Searching the publicly available Suffolk Deeds web site shows the city of Boston has filed over 100 Instruments of Taking against the Stamatos family since 2002. And you'll also find the corresponding Release when they pay the taxes during the period the law allows for the owner of the property to pay off the taxes owed.

But whatever, let's just make shit up about how your city takes more action than Boston, when really they both follow exactly the same procedure that is laid out by Massachusetts law.

....the city also earns interest on the outstanding balance. The money gets paid, eventually.

The law is very clear that it is a taxpayer's responsibility to secure their tax bills if they don't get one and to pay their taxes in a timely manner. Per MGL C. 60, after the end of the fiscal year (on June 30th) and taxes go unpaid, demand notices are sent out and then notice is published (these are done automatically in most towns). Then after that an Instrument of Taking is issued and put on record at the Registry of Deeds giving taxpayers six months to pay their arrearage. Only after that six months can the City move forward in the Land Court to foreclose on its Taking. After a city or town petitions a case, the Land Court has to determine who is entitled to notice via a title exam, and sends out notice. Because tax lien foreclosures can result in full loss of title to a property (even if the outstanding taxes are a fraction of the value of the property), the cases can't move forward until all parties that have any sort of legal interest or encumbrance (mortgage company, lien holders, condo trustees, water district, etc) are notified, and sometimes that means the petitioning party (IE a city or town through its city solicitor or town counsel) searching several dozen heirs or heirs of heirs, if a person dies intestate, or tracing someone who skipped town, etc. As someone who has done work in the Land Court, I know that most cities and towns will usually work with a property owner to resolve a matter (besides the huge liabilities involved, cities and towns don't want to be landlords when they obtain occupied properties, and almost never evict tenants when that does happen -it's just too politically unpopular), and usually only push for a foreclosure judgment if a property is abandoned, a nuisance or vacant land. Not to mention, the Land Court's Recorder (the magistrate who conducts the Tax Session) usually won't allow a Judgment to go through unless it's a last resort, and then the Land Court can still vacate that Judgment for up to a year after it is allowed, if the property owner can demonstrate an ability to pay the lien in full.

overpriced luxury condos no one wants or can afford

Uh yeah, that's why they all get sold quickly, to buyers paying cash. Because no one wants them and no one can afford them.