You’re conflating two things that are not quite connected in the way that you think they are. Comics didn’t disappear from those locations because of the shift in distribution, the shift in distribution happened because comics were disappearing from those locations. As an item, the comic book rack wasn’t generating enough revenue-per-foot as many other things, and so those newsstand outlets gradually but consistently stopped carrying comics, regardless of their returnability. They weren’t worth the effort to stock and restock the racks for the relatively meager profit they generated in those outlets–a cigarette machine or a soda machine or a video game generated more profit, and with less maintenance. It was evolving and switching to the Direct Market that saved the comics industry–without that shift, mainstream comics would have died off by, at the latest, the mid-1980s.
You mean other than digital comics, selling through bookstores and Amazon, and mail subscriptions for comics? I know...