The whole concept that we as a younger generation need instant gratification with our media leaves a bad taste in my mouth the same way when someone says "kids these days don't read"
It's such a stereotype that makes no sense. This is a generation that waited years for the end of Harry Potter. (Or nine years to see Ted meet that damn mother) And will willing sit down and watch all 7 star wars or both the hobit and lotr in one long go. Movies are literally splitting movies into two or threes because they know well watch it. So long form media is still alive and kicking and we love it. ((Do you think steven universe would be as popular if they removed that long running story??))
we expect gratification from vines and gag a days, but that's because we expect that from that medium. We are not going to read a story and expect everything right away. We want different things from different forms of media.
same with comics. I read alot of long comics and i love them. Sure it takes a while but that allows me more time to love it. Long form comics may take their time. But audiences still read them enjoy the.
Also i have seen many different long term webcomics that have a active fan base that makes fan fiction, fanart, fan comics due to their being alot more to work with. But while i know they exist i have yet to see fan fiction for a gag a day yet