Price is the problem. I thought digital would solve that; but the last time I looked, Marvel was charging the print price for a digital comic! That was a long while back, though; I haven't cared to look again after seeing that paper and distribution had nothing to do with the pricing scheme.
What needs to be done is a netflix model for comics. I pay 20 bucks a month, and I get limited time access to a set number of comics during that month. It can be new stuff or back issues or whatever; but I get access to more for my money with the freedom to sample on a whim without spending more money.