Readyloads came quite late so they are relatively new, a mid 80's introduction, they were relatively expensive compared to plain sheet film, I won't miss them at all.
The films I really want to use were never available, carrying Darkslides is no big issue but when I still shot LF colour then the Polaroid (Fuji) 100D was useful, the failure rate was an occasional problem, but the economics aren't right now for the film companies, sales have always been quite low now it uneconomic.
If someone were to make a new alternative to a Grafmatic back that would be different, or a new styl self loadable film pack.
Ian