Did sales die? If so, why if it is so super??
LOL, nah the sales did not die, but they barely got out of nappies!!!
These were ghastly when first released. Took Roland a few years to get it right, (and even then not fully) but by then the damage was truly done. The same is true for the Fantom line.
Truth is Roland are now making so much money from their piano range and piano based range of arrangers and organs that they have no desire or need to go back to producing major arranger keyboards.
They may release a "new" Fantom type synth WS, but I wouldn't be holding my breath.
The only reason they came out with the BK module was to augment the home piano range.