Well, thanks to the rest of the series, we do have more or less the full life history of Chateau Picard. It belonged to the Picard family before WWII. Whatever was happening economically around it, somebody let the Picards keep it up to TNG times. I guess Robert's widow Marie was just hanging out there between Generations and sometime after Nemesis, and then fucked off for Jean-Luc to "inherit" the place when he retired? I mean I guess we're only told that they don't have money, not that they don't have landlords. One thing that can be said though, it seems that it's been an active vineyard in the "present" era and everyone who's lived there has been actively producing wine, and by extremely traditional means at that, until the beginning of S3, where Picard and Laris are leaving and packing up the house but not exactly moving out?
One might suspect that the Federation actually isn't very good at socialism.