It's related to something I've struggled with; I mean, I make users take active action every bill... I don't support recurring billing, just 'cause I feel weird about just hoping you won't remember to cancel your account. And yeah, I'm probably loosing out on a lot of trailing months... but what do you think that does to customer goodwill?
I'm not saying I know the answers... however, my opinion would be that long term, you are better off providing enough value that the customer is willing to take active action to stay.
On the other hand, I've had several customers ask me for recurring billing, so it's quite possible that the convenience factor is the operative issue here, rather than the value provided by the service. It's possible that the service is worth the money, but not worth the hassle of positively acknowledging another bill.