Yeah, at least in France, land can't make you noble, even if it's a whole noble fief with a title attached. (Then you're just a rich commoner who owns a title but can't use it.) You could become noble by holding certain jobs for a long enough time (usually three generations), though. And people did buy those. (Not through bribes - the royal government sold certain official posts to raise revenues, so it was legal.)

There was also a sort of real estate boom after the revolutionary government passed some laws to make it easier for commoners to buy land, which was sort of like what you describe - all the farmers who could afford it would buy all the land they could at higher values than it was worth, because it made them feel like they were rich landowners.