Well, squeak, I think the problem is two-fold.

Firstly, you have the problem of sound-set. As already stated, ROM is not infinite, nor cheap, and hiphop and rap styles change so fast that no manufacturer can keep up affordably. But samplers don't suffer from this problem, they can have HUGE memory RAM amounts, and often have very advanced filters and dsp for tweaking.

BUT....... their weakness is slow load-up times. When, oh when, are the big three going to bring out ANY sampling module or keyboard with USB2 or Firewire on it? 512MB of memory transfer is an eyeblink to a computer, and ten minutes to the fastest samplers, completely unusable, live.

Secondly, and most problematically, the main problem is style creation. For something as fluid as the hiphop scene, a constant supply of fresh styles is going to be the only thing to keep young rappers happy.

BUT........ until someone brings out a copy protection scheme for styles, what is the incentive for a young, hip style creator to develop them, when they are being traded around and given away like mp3s? Sure, the ROM styles of a new arranger get due care and attention, but what happens after that? The manufacturer makes his money from the style creation off the sales of the arranger, but once he has sold it, he makes very little further money from continued style creation. He sells a few, but then everyone trades them around, and the money is gone.......

What is needed is a combination soundset and style that has hardware protection keyed into it, somewhat like the system UAD and TC Works use for new plug-ins that run on their hardware cards. In other words, you buy the sound-set (the drumkits, bass sounds, voice tweaks) AND the style as a package, AND it is keyed to the unique sn# of your arranger's motherboard. So it's not possible to copy it and give it away to your friends.

You can still tweak it further, and use the sound-set for your own styles, or adapt older styles to use the new sound-set, but you can't give it away....

The style creator makes a lot of money (at least, enough for him to make it worthwhile to do more) guaranteeing a continued supply of fresh beats. Everybody wins........

Until the problem of copyright protection is addressed, it is unlikely that we are going to see a lot of development in contemporary styles.