Honestly, if a comic isn't working for you, quitting might be the best thing to do. There's no shame in looking back and saying "I don't want to work on this anymore."
You'll still transfer over skills from your previous projects, and you still would have learned something from your unfinished comics. BUT- you should try using what you've learned about your work and process to plan for success. Find what works for you to make sure you get your project done if that's what your goal is.
And for me, I don't tend to look into authors much. If I like the story, I'll read it. However, if I notice an author I'm familiar with keeps dropping projects consistently, I'm less likely to read as I don't like to be left without a conclusion to the story.
But, keep in mind that unless you're super well known, people aren't going to know if you have unfinished projects most of the time. I created a test comic I knew I wasn't going to finish as it was just for me to prepare for my long term project, so I made sure to let my readers know. The people who read my current project likely won't know about the other one. Just know your goals and what's achievable for you.
