Yamaha and Korg arrangers are still around because of better marketing/sales, so their arranger product lines have retained the continued support of management. Not because they have a better system for simplified chord fingering. Roland's was first, not perfect but quite good. GEM, (and for the last nine years or so) Ketron and Casio, have very similar systems. I can play most songs on their boards without re-learning. (It's harder to "unlearn" a song that you know than to learn a new one!)

But because of Yamaha's success, most of today's hardware and software arrangers have added a fingering mode that emulates Yamaha's; for all its faults it has become a quasi-standard enabling people with no musical training to play a limited repertoire of chords. What I've been trying to communicate here is that the "Roland system" is an alternate quasi-standard, with greater merit to be preserved and promulgated. If Roland really has abandoned the arranger market, they should put their Chord Intelligence in the public domain; bake it into the firmware of their MIDI controllers like the A-800 and license it to Ableton, where it can benefit future generations of music-makers. It lives on in the recent FP-E50 and Go:Keys 5, so there is hope.

One tone per key was a physical necessity due to the construction of the pianoforte and organ-type instruments going back to ancient Rome. With electronics we've moved beyond that constraint. Perhaps even beyond the form factor of the black-and-white piano keyboard! I've spent years of my life NOT learning to play the organ (largely because I never had a realistic opportunity while I was young), but instead learning how to cover songs in the easiest way possible. There were no clip launchers in the '70s or '80s. At the whole song level, you could make a mixtape. Getting more hands-on than that meant a chord organ or autoharp, which were fine for the casual musician playing carols 'round the tree. Things got much more difficult (and expensive) from there.

Somewhere through the decades it seems that a philosophy took root that no one should be a casual musician. "If you're going to play music, knuckle down and learn your scales! Otherwise, just play a tape!" As I've gotten older I guess my world view is going away with me, and I think that's unfortunate. Arrangers with all of their proprietary gimmicks are an excellent bridge for the musically curious. And if there IS an easier way for someone with minimal training to cover pop songs and standards, I would like to know about it!!