Information services that are transmitted over the internet require that I have an internet connection. They don't require that I have a particular internet connection. Cox is arguing that they do.
I know you work in email, and email represents a large portion of total internet traffic. (Less by the day, with the advent of streaming video.) But how much of that email is ISP email?
In a totally unscientific survey, I've got over 8,400 names on my mailing lists. Gmail, Yahoo and Hotmail account for more than 4,900 of them. So your earlier "threat" to delete mail after three days? Would affect less than half my readers.
If anyone actually tried it, a whole lot more people would decouple their email addresses from their ISPs. And once that lock-in is gone, what's to keep them from switching to a new provider? That's the only reason ISPs provide email any more.