The advice given to new creators is that they should start with a smaller project. It's good advice to follow since a short project allows a creator to gauge how willing they are to do comic creation and it's a good learning experience.
The thing is about new comic creators is that often times they are also new to creating art in general. Maybe they've been drawing for a year or two prior, maybe even less (plus comics aren't just about making a nice illustration). They're also new to writing stories and characters. And all that ignorance and inexperience related to the art form bleeds into the work.
The average reader is likely looking for a polished project to get into without having to worry about experience level of the creator. Usually it's other creators that are more forgiving when it comes to reading new work made by a new creator.
It could be that, especially if specific readers have been burned by a new creator in the past that didn't complete their comic.
Honestly, it's just patience. Work on bettering the quality of the comic whether that be in art work or writing (referring to creators who write and draw their comics).
I think you're right about how having other platforms to show off your work is very useful, though I don't know if Lavendertowne is the fairest comparison for the newest of comic creators since she had been drawing almost all her life and she was going to art school at the time of starting Unfamiliar.