Bringing this back because I've been thinking about it.
Haven't come to any conclusions, yet, though....
the only insight is that I really want it to eventually finish. Printed stuff, I tend to assume has an end already; some comics and graphic novels seem designed contrary to that and it always catches me off guard and disappoints me. Webcomics are harder for me to take seriously unless someone is introducing me to a webcomic still online that is completed already.
(Like
"Bite Me" by Dylan Meconis, or
"7 Extraordinary Things" by Doug Lefler or
"Digger" by Ursula Vernon, although that one I found while it was still running, which was nerve-wracking.)
Other than that (and wondering how the completionist notion fits into expectations with length; shorter things might finish faster, but they also might be a sign there's not much commitment), no conclusions yet.