If I'm being brutally honest, seeking popularity above everything else is a setup for failure. You will never be satisfied with your engagement. You will always compare yourself.
And getting your level of engagement is a dream for many many people.
I understand your desire for growth, of course everyone will have that to some degree, but you should never quit because you aren't getting "fame." If you are having those thoughts, return to your initial mindset. I'm assuming (hoping) that you started this comic because you love to draw. because you love to write. and because, in the end, you are your most important audience. It's about what you like to do. It's about you enjoying your story. It's about whether or not you are having enough fun on your own, discounting all the stress about engagement.
You are an incredibly talented artist. I hope you can grow to see that. I want you to be able to continue this comic, because it's both beautifully drawn and successful, and I want you to accept that. but obviously, if you're truly not having fun, then you shouldn't feel obligated to continue.
If you'd like detailed feedback, you are welcome in the forums always.