Absolutely not. The crap that Rare has pushed out in recent years did nothing but hurt my desire to buy a 360. They have yet to release a single title that I would even want to play, let alone one I would actually want to buy. Microsoft should have closed them out rather than Ensemble.
I don't know why the death of the Dreamcast would convince anyone to buy a 360 though. Admittedly it does seem to be gathering all the great fighters of the system onto XBLA so it might have some appeal there. That is a relatively recent phenomenon though.