For me at least, the bigger issue isn't quality of the comic (although that can certainly be a factor too- the longer a comic goes, the longer you have to commit to the skill level you were at when it started as reader's first impressions lol), but more so the amount of time to completion and in some cases, pacing issues.
For example, my 2017 reboot I felt pretty solid about the quality of the opening pages tbh. I'm better now than I was then but looking back at those pages I'd still be proud to introduce people to my comic I think but the reason I dropped it at the 2 month point is because I took a step back and realized at the rate I was going (1 page per week), accounting for roughly 20 pages per chapter, it was gonna take like another 10 months to reach the first cool action scene... in this action fantasy story. Problem was twofold- I was too slow at putting out pages to draw that particular story in a timely fashion, & the writing was paced poorly relative to my skill level/speed. When I wrote the basic plot back in middle school I had been inspired by the long running anime fantasy action series I loved... but what I didn't realize is that those stories are drawn often at a 1 chapter per week or month or whatever rate. The pacing works in those stories because they're drawn so fast. My noob ass was taking the same pacing and drawing them at a snail's pace and was going to release them at that pace as well, which would have probably been super boring to read
That said, I do think that trying out that 2017 reboot actually was pretty helpful in regards to the comic I ended up writing in 2018. By seeing what wasn't working, it helped a lot to inform what length of comic I should actually be working on as well as what kinds of edits could be made to keep the pacing more concise and moving along and exciting. I think I would have gotten all the same types of drawing and scripting practice if I had continued with the reboot, but I wouldn't be nearly as satisfied with it being on chapter like 5 right now vs. My complete 70 page one shot I finished in December
Edit: And There's actually a new long form story that I've thought of last year while working on my first one-shot that I'm really interested in working on in the near future, but at the end of the 70 pager I came to the conclusion that my speed still isn't fast enough yet, so I'm working on another one-shot sequel to the first one instead I'm hoping that maybe in the next year or 2 I'll improve to the point I can work on it, but I really want it to be good and fast lol