As somebody who did really quit comics for nearly a decade and who has worked as an illustrator for a long time, I can probably weigh in here.
One of the biggest problems with working as an illustrator: No real career progression.
I was devastated when due to lagging behind my peers a bit due to a rural upbringing I missed my chance to pitch to or get taken on by publishers before the 08 financial crash made them all close down open submissions and stop taking risks on new talent, and so had to diversify my skills and become a games artist while they all worked on comics! But then several years later, my friends, doing my "dream job" of being full time comic artists started coming to me at events asking how to become games artists. Turned out, yeah, sure, they were drawing comics full time... mostly of other people's IP, and not particularly good IP, we're talking like.... BRATZ comics for French kids mags and vanity comics about terrible Youtubers, and their pay hadn't gone up or anything. Only one or two had managed to get bits of work from Marvel and the like (not on mainstream titles) and these people were basically only making a pretty basic income.
When you become an illustrator, there's this assumption of career progression, that you become more and more famous and respected, work on bigger and bigger things for more and more respected publishers, or at least get a bigger and bigger audience, but it's just not the case. My friend had worked with a really, really famous writer and then afterwards was asking around if anyone had commissions going. Hell, I had work published in a BBC Doctor Who book last year, and then had to get a full time job immediately after because I was struggling so badly to pay London rent. Sadly it's just not the case that you do one big gig and you break in, and for some it isn't even the case that you'll steadily accumulate die hard fans. I have a big social media following that can be super-helpful at times for promoting my art stuff, but it mostly didn't come from art, it came from er... making viral D&D jokes9.... and voicing a character in a dub of a really popular webcomic13...
What I'm saying is, being an illustrator or comic artist is a slog that doesn't pay well, and the only reason to do it is because you really, really love doing it and you're willing to sacrifice time and lifestyle. But after a long time, the slog weighs you down. You see your peers on exciting new projects, or hear that they've been promoted to a midweight person who works in a bank and now they earn like twice as much money as you and can afford like... clothes and stuff. I'm in a pretty great position right now because I've managed to work up to being a creative consultant working part time, while the other days of the week giving my comic a shot. It's a great place to be because I'm not financially reliant on a publisher and can draw my own original IP, and I got to it by putting aside comics for a while to build up my career rather than by trying to build up a career in comics that wasn't going anywhere.
If you've been drawing a comic for eight years, it's probably pretty much as popular as it's going to be. Comics sometimes explode in popularity after 1, 2, 3 years, but... not so much eight. No, generally after eight years, people have seen it, know what your comic's deal is and whether it's their jam or not. Unless suddenly it gets taken on by a publisher or gets adapted to a new medium like animation, it's likely to just remain steady. So if your comic is of decent popularity, but it's really only enough to scrape by on similar money to somebody who tends a shop till, and nobody ever writes reviews about your comic any more and you're just slogging along... well, yeah, you might really feel like you want something exciting and a shot at making something that's more than just "kinda popular", or to experience "having money".
Plus ... well, I just rebooted10 my old comic9. I can't even imagine, looking at the old comic made by me like ten years ago, working on that version of the comic now. The me who made that comic was like a different person, she didn't even know she was gay, yeesh! (Hilarious given that I'm now engaged to a woman, I don't think she'd even have forseen that, never mind living in London!). As you grow as a person, you may well improve in your storytelling as well as art, but also the themes that interest you, and your depth of understanding of those themes changes. John Allison's switch from Scary Go Round to Bad Machinery happened because he was in his thirties and felt like doing a comic about trendy young adults in their early twenties didn't fit him any more, he wasn't a trendy hip 20-something any more, he didn't know what that group were into now, but he knew it wasn't the kind of music and fashion that he'd been into at that age and he'd just feel like he was getting dated and embarrassing. I would similarly hate to be chained to the tastes and oblivious storytelling decisions of my past self.
So... yeah. I know it sucks when a comic you really liked ends, but it happens a lot and it's worth sparing a thought for just how much hard work and sacrifice goes into making a comic for such a long time, and saying some words of kindness and encouragement to the creators.