This thread has some incredible information if you're interested in the topic. All about the old 4-color letterpress printing on pulp paper. After the colorist made a guide, somebody had to cut each of the color layers by hand, in order to make the plates:
It resulted in a unique look that defined comics for generations, and with its disappearance there seems to be (as in the case of other commercially obsolescent printing technologies) a growing interest in it among artists. However unlike other old-fashioned printing techniques, which are expensive enough, I doubt that artists will have access to this particular technology unless something unlikely happens, such as a determined person (with money) or a collective revives it and makes it available. Or some university or other institution.
I wouldn't want the tedious job of cutting all those separations, but I do like the look that resulted. As many have said, the limitations themselves created a certain aesthetic within which the artists had to work.