They will blame the punchline thing on deadlines, but if you struggle to think of one joke a week, maybe you were never good at comedy to begin with. Most of these people aren't actually funny, but they get tons of likes so they THINK they're funny. And most of these people also, despite being insanely popular, have next to no connection with their audience because their audience doesn't give a shit about them, they're just the, "oh that looks familiar" person. That means their fans don't care about "them", they just care that they're getting cute comics for free.
So when they branch off to original stuff and see like, a 90% drop off of their fan base, they get terrified and crawl back. Then create a non-stop endless cycle of perfectly manufactured comics meant to hit the exact buttons with predictable character expressions and lazy art.
Most people don't make webcomics out of passion, they do it for exposure or for attention. Look at how many of them want to be in the /co/ industry and experienced artists always tell them, "Start a webcomic! It's a good way to get noticed". That means every person and their grandmother has a webcomic now. So the actually good webcomics get buried hard and you need to pander just to get noticed or accept your slow climb to having a fanbase.
AwkwardZombie is probably one of the few good consistently updating webcomics left.