I agree with you on this! There are definitely outliers but the majority do have pressing issues that don't have anything to do with what's popular or their marketing ability. I'd say a lot of people don't even have projects that are QUITE ready to even be marketed yet.
It's hard to discuss on the forum because people take this type of thing very personally but I think a lot of people have a LOT of trouble being objective about comics that are popular and I think having more objectivity would even help with their own work. But instead people see something they think looks kind of dumb and silly and think "Why is that comic popular and mine isn't?" without objectively being able to see why it works. It's never by some weird marketing miracle that makes what some people might think is absolute garbage turns out to be extremely popular. It can be helped by marketing, but it HAS to be marketable in the first place.
I've just stopped talking about it altogether but it's hard not to chime in as someone with some level of professional experience both in webcomics, print comics, and SOME experience mentoring. I still like to interact with anybody who does comics because we all like the same thing and I think that's COOL. But I could not recommend a lotta folks to any editors, publishers, or agents in their current state. And that's FINE since its just a fun hobby for most and the more they work at it the better they'll get eventually. All of the time spent complaining about how hard it is to get popular and figuring out how to perform marketing miracles is better spent learning and focusing on the craft.
Also, just be nice to your fellow comic makers because everyone is working hard even if you don't like what they do. Plus, there are waaaay more benefits to being friendly in the long run (in the way of both best friendship forever and networking).