@Mame,
Because I've been today in a neighbour town (actually, the town borders are only a few hundred metres away), which formerly was ...
... an independent state (earldom) of the Holy Roman Empire until it became mediatised in 1807 ...
In 1822, the last prince (and earl), Aloys von Kaunitz-Rietberg, sold the county - by then an allodified fief - to a bourgeois merchant (who actually was a progressive/early democrat). As a non-aristocrat, however, he was not granted any rights of nobility.
In a compromise, he received the count's landed property (to this day thereby an industrial family
Tenge-Rietberg), the title of nobility fell through hereditary claims to the
House of Liechtenstein (Prince of Liechtenstein, Duke of Troppau, Duke of Jägerndorf,
Count of Rietberg).