Comic books lack an air of accessibility and the "special" feeling. It's just not like, say, reading a big Harry Potter book the way everyone went mad for those last 3 books. 70% of everything in comic books feels.... light and disposable. Then they suddenly need big events to make their books feel special, but the events are so 'crossover'-esque and so lacking of anything real that they end up becoming MORE like the stereotype of comic books, not less.
Every so often you get something like a Sandman or a Watchmen, something that feels "special", substantial, like you're reading a story that means something, it gets passed on down the years, and every few years there's a new crop of people discovering them......... ongoing superhero comic books cannot match that. Accessibility isn't just knowing information, it's making you care enough to want to know the information. It's about giving stories meaning with good writing, beginnings, and endings. It's about cultivating an "aura" that makes people not into it, want to be into it - something you can't do with light, splashy, event-y books - with so much convoluted continuity, and most of it is continuity nobody but the hardcore care about. It's like trying to compare one of these 20 year long soap operas, the young and restless, to, say, The Wire. In fact that's a good comparison, most of the comic book industry is the male version of daytime soap operas.
And then there's the ass-backward system of the direct market.