It kind of makes sense really, Ferrari are owned by Fiat, Fiat have a link with Yamaha (hence Rossi riding a Fiat/Yam in MotoGP), Suzuki already have both car and bike (albeit the cars are a bit rubbish).
In the ever increasing sectors car manufacturers are trying to get in to, motorbikes makes sense, they get to have another market sector, and with congestion as it is, the sales are only going to get higher. Porsche have bought a controlling stake in VW to retain it's own sales (the R8 is going to give the 911 a kicking - mind Nissan's GTR at have the price is going to create waves!!).
In terms of mucking Ducati up, that will be the current owners job to ensure the brand values etc are retained. If ducati's were a bit more reliable, and cheaper to maintain, I prob would have got one instead of the FZ..