Style copy protection has been something I've posted about several times in the past...
Without it, essentially you are pretty much limited to HAVING to buy each new model to get any significant number of new styles, as the manufacturers use the newer sounds and OS features as a kind of dongle.
I'm sure that the style developers themselves that make the ROM styles would LOVE to be able to make these things on a more than a three or four year cycle, but if they can't copy protect their work, it is pointless. There is a culture of trading styles around like bubblegum cards that ensure they would only make a tiny fraction of the revenue they deserve, hence, no new styles.
I guess the problem is, if the manufacturers DO implement a secure style system, they might lose sales as many here start to realize that they are probably buying a new arranger more for the new styles than out of any REAL need for it's sounds and OS features.
What's a poor multinational to do...?