You are looking at this so simplistically, and through very uk centric eyes
firstly, the data bases are not searchable by name or date of birth.
secondly, it should be obvious many of the countries round the world inc Sierra Leone have poor/ incomplete record keeping as well as being corrupt.
thirdly, ardit is Albanian. Somehow we manage to confirm he doesn’t have any property in Albania. What about the farm he owns in Russia? What about his families property portfolio registered under his father, or a corporation? hardly foolproof
fouth, HMRC is irrelevant. They don’t share records with housing associations and local authorities plus it’s very likely someone could own an asset that produces no income at all- an empty property, one that they let a friend live in.
not all countries are like the uk. Owning a £10k house in the Albanian countryside doesn’t bring the rental opportunities the uk does. They may also simply own land.
it’s a blunt instrument and even with all the above which makes it a useless check, you’re ignoring the fact that this searching mechanism doesn’t exist.