Or a Roomba... One of the first things they want to do is make a plan of the house.

But also, don't builders have to submit plans of homes to the local government when building them for approval?

Most robot vacuums (at least the ones that use LiDAR, which seems to be the majority) can only capture a very rudimentary plan of your house, that being a 2D image taken at an elevation of ~10cm or so. It will also be obstructed by any large objects, and there's no easy way of telling them apart from walls.

Your government probably knows your floor plan (though, I don't think they tend to be publicly accessible). Either way though, neither of these methods are anywhere near enough to do what was shown off in those Wi-Fi tracking demos. Here's hoping the tech doesn't get a lot better or has a series of unexpected breakthroughs.

Or a robotic vacuum. Or one of the other thousand houses with the same layout in the neighborhood

Floor plan isn’t enough for a location model. These have to be learned in from accurately tagged data combined with measurements taken at the precise time of the tagged location data. A lot of tagged data.

You’re not going from a floor plan to a precise location model. Just think about how different the WiFi environment would be if someone put their router next to their steel computer case versus someone setting it on a nice MDF cabinet with no wires nearby. Completely different RF environment and pathing.