On History: Microfiche
I was musing, though, on the microfiche reader I picked up several years ago, and the 100 or so old 1940s comics I have on microfiche. The technology itself is old, and had already been around in some format for decades when it started to become commercially viable in the 1920s. But what's interesting is that was really only about a 10-15 year window where selling microfiched comics was a financially viable endeavor.
Working backwards, it's easy to see that the proliferation of the internet would have pretty well killed off whatever market was still around ten years ago. For the 5-10 years before that, there was a weird mix of models available. Some folks were trying to host stuff online, but internet speeds were too slow to make that a good option for anyone but the very patient. CD-ROMs were tried but you would run up against size limitations -- I have the first 500 issues of Amazing Spider-Man in this format and it's a dozen discs which, while not an unmanageable number, is still kind of awkward and tedious if you're trying to read a story that might run from one disc to another.
(Personal aside: I just realized that both my work and personal computers don't have drives available to read these discs any more!)
Before that, in the absence of a robust reprint program, the only other real option for reading old comics was microfiche. However, the potential audience for such material -- comic fans that had a few hundred dollars to drop on a reader and some comics -- probably didn't reach anything resembling a critical mass for commercialization until the mid-to-late 1980s. Microcolour, the place where I got all of my microfiche comics and materials, was started in 1988. I don't know exactly when they began adding comics to their catalog, but there's a "Collectors' Alert" on their site that implies that they only first began doing comics with that notice -- a PDF with a 1997 creation date.
Their list of available comics has a 2003 creation date, and I received notice in 2007 that their film supplier had dried up. Their website doesn't seem to have been updated since 2011, although the domain name itself was renewed last August so they don't seem to be out of business. But it points to this very limited window of time that the company really worked in, just as the last vestiges of the analog world were giving way to the digital one. It somehow seems emblematic of the general chaos the comic industry was in during the late '90s and early '00s.