> how is ownership established if there is no single source of truth?

Oh, boy, let me tell you it is very disconcerting to pay a title company to do a search of legal records on a property, and the only guarantee they offer in some states is that "we didn't find anything suspicious but there is no guarantee that someone from the past won't pop up with a better claim to ownership. You can't hold it against us if that happens." How is it that most people making the biggest purchase of their lives are going along with that? I'm definitely not okay with it, but sometimes you can't buy property without accepting it- no title company will offer a stronger guarantee.

For details, I'm talking about how in some states the Special Warranty Deed is the standard for real estate purchases: https://www.legalzoom.com/articles/what-is-a-special-warrant.... A title company will guarantee that the current seller hasn't entered any agreements that might legally obligate you (such as offering the property as collateral for an outstanding loan), but they are very clear that actions of previous owners are not included in this guarantee. So there is no single source of truth- we just hope that we're not part of the tiny percentage where the special deed is insufficient.

Edit: for context, there is a distinction between title insurance and the deed itself, but the title company is only offering insurance on the deed, so if the deed only covers the previous owner then the insurance only covers that too.