It's a chicken and egg problem. Did the publishing industry create the demand for dumbing down their readership? Or did the public demand the publishing industry dumb down their books for them to read? I'm stumped as to having an answer to those questions. Thank you for introducing me to a new word. I've never read the word 'glom' before now.
You might well ask what makes voters glom on to Donald Trump. What's the secret there. It's certainly not quality.
Mostly a really good ability to tell a story. Moreso than plot, technical writing ability, etc (though those are also important). What goes into that ability to tell a good story seems more nebulous. When you write books that have my teenage daughter, who wasn't much into reading at all, sneaking into her closet with a flashlight to read until all hours of the night, there's something about how you're telling the story that is compelling. Structure, character, choosing what to dramatize, etc.
But I would also say, there are a lot of things like theat, like reasons, and a lot of different audiences. You have to find the one that fits for you.
I was going to only self-publish, but after a couple months here on this forum I think I am going to try as Jannert listed above. I think I will give myself a timetable of 9 months to a year, if nobody bits and I have good feedback from beta reads, I think I will then self-publish. Again, before I was 100% self-publish. While waiting to see if I can get a publisher, I will continue to write more. Anyway you that you choose to go forward, good luck and make sure you post here so I can read your story. There are so many talented writers here, its intimidating for an old man like me.