Leading 3D printer company joins the multi-material printing trend.
Creality unveils multicolor 3D printer for under $500 : Read more
Creality unveils multicolor 3D printer for under $500 : Read more
The now-defunct M3D had the full color CraneQuad.There are full colour 3D printers, they are just very expensive. Stratasys have a line of them called Polyjet which can do multi colour and multi material.
So your statement, "even the best 3D printers are limited by the color of the spool of filament (or vat of resin) they use. ", is wrong.