As far as the price of high-resolution color goes, we're looking
through the wrong end of the telescope. PCs and associated gear are
cheap now, but hail back to the 1980s. A really functional 5150
(memory, graphics, disk drives included) would probably run close to
$3K. For that you got a 64K 4.77MHz system.
But in fact, as early as 1986, megapixel color cards were offered for
the PC platform--and before 1990, relatively advanced TIGA cards were
offered by several vendors. The PC was beginning to compete with the
high-end workstations and good graphics were a must.
So arguing that color was expensive, is a nonissue. Everything was
expensive, save for the "home" computers such as the Commodore Amiga.
What I do credit the Next cube for was the use of Display Postscript,
although it wasn't the first to do that (Sun, IIRC, was).. The MO
drive was just plain silly (slooow write, specialized media).
--Chuck