AstralV,
I will take your core question the way I'd take it: I remember when Roland had a pretty regular release cycle of the SR-JV/SRX cards for the XP-->XV series; they ended up with a good collection, well organized, very playable and inspiring soundsets for a variety of genres.
Then came the last few in that series, things like the Supreme Dance card on the one hand, and the card with their best piano sampleset on a card, the two extremes.
Again, I think a big factor is the change in the market. It's possible now to get a very wide selection of samples with software on a PC or Mac; whatever Roland might argue about the superiority of their programming or sound design crew for their cards, I suspect at a certain point that fell on deaf ears, when people could get (and I'm talking the mass-market audience) "good enough" for a quarter of the price ($50 for a sampleset or CD or online vs. $250 for a Roland card). Alternately, the competition for high-quality samples has also heated up, since the days of Gigasampler's debut onwards. You can argue, reasonably, about the validity of that approach to sampling, whether it really accomplishes anything, but bottom line, the market bought the concept, for a long time.
Now, it's clear Roland is concentrating on fewer/better. They are releasing the ARX cards much more slowly, with a lot more focus. I don't think we'll get a "Vintage" ARX card any time soon. It's questionable whether such a thing would even be sellable. ARX seems to be much more focused on high-end emulation of very specific things through sampling -- covering an area of the market Roland hasn't gone after before. At least, in this way, they're breaking new ground, for them.
Another perspective: most companies end up having a suite of sound designers around the world who work with them to develop a soundset. In Roland's most successful period, Eric Persing was really at the core of what made many of the SR-JV cards great; then, he split off to form his own, very successful, business. That generation of sound designers, too, was much more, in my opinion, tuned in both to the sound of vintage analogue synths, and had much greater literacy both in the areas of music theory and practice, and in the area of electronic synthesis, than the current generation of sound designers. For whatever reason, and it's much like what has happened in all the arts in the west at least, there has been a dramatic falling-off in creativity, originality, inspiration and just sheer educational foundation over the past decade or so, it's quite appalling. Personally, I attribute this to the 30 years of benighted Republicanism and conservatism that has essentially destroyed the west's ability to influence or guide the future. But, that's just my grumpy perspective.

So, I blame Ronald Reagan for Roland's failure to release inspiring soundsets any more, basically. Him and Margaret Thatcher.
And a third perspective: sheer market forces. These probably factor in more than anything else. Keep in mind Japan has been experiencing basically a prolonged economic downturn ever since the early '90's, it must be souring the mood over there quite substantially at this point. We're likely to follow suit in the US and Europe for the next 15 years.
And then a micro perspective: Roland's recently acquired Cakewalk, with its fantastic collection of expertise in a variety of areas, from DAW interface and software design to incredible synths and samplers like Rapture and Dimension. I don't discount a period of integration between what Roland has done and what Cakewalk has done over the past decade that will only bear fruit down the line in more substantial ways.
Does that help you?
