This is scary for new creators too. It's possible to have a great product and just not be able to get readers to pick it up.
Marketing plays into this stuff too. I wonder how you make people aware of something when they're inundated with advertisement everywhere they go. It used to be you could just do a wacky cover, or an alternate cover, etc. and people saw that as an incentive to try something. People hate that now. The question is, what do you replace it with? I try comics on a lark. Sometimes it's a creator, sometimes it's pretty art, or sometimes the story appeals to me. But I can't really pinpoint directly what it is that causes me to buy something new that I don't normally read. Hype sometimes. Like "Invincible". Or a creator who I love like Peter David. Heck, Bomb Queen made my list just because the creator was nice to me on a messageboard. It's just so random. I wonder if that kind of environment is what's killing all these comics.
On a sidenote-- I loved that "Impact" line. The Fly ROCKED. I picked up The Comet too.