To the genesys,
That would be ideal, but would have limited sales. Well if Yamaha went out with such a concept, would the die hard Roland or Korg fans buy it? Well, some of the would buy it, but not all.
But things like these are generic Keyboards....they don't have a "distinctive brand" name on them.

Would Yamaha want to sell something below cost (the business sceme with things that act as a base for software is "lose money on the product and earn money on services and software" Gilette sells cheap machines and expensive razors, and Sony selling cheap Playstations with expensive software and royalties) that costed a fortune to develop, only to see it used with roland styles and sounds?
Nah, I don't think so.