Couple the increasing property taxes on vacant homes with an agreement that there are no property taxes on properties leased for free to qualified individuals (people who would qualify for government housing anyway essentially) and the government will pay for repairs. The government gets a cheaper place to house the homeless, having only to pay for repairs, the landlord gets an appreciating asset with no repairs to worry about, and the homeless get a place to live. Seems like a win all around unless I’m missing something.
Maybe I’m oversimplifying but I tend to think money is the problem. Supposing all wealth were equally distributed, libertarianism makes a lot of sense to me as maximizing personal freedoms. It generally becomes a problem when people use wealth to abuse others, either by hoarding wealth and restricting the freedom of others that way, or by using inequality to purchase things that no person should be able to purchase.