I have a slightly different take on the issue of email dependency from the viewpoint of someone who runs his own email server. Because I'm not an ISP nor do I have the resources of one, I run a single server which is at the mercy of crashes just like any other server.
If it goes down, I don't have redundant backups and such so I have to manually reboot the machine to get it back up and running.
This becomes difficult when I'm not at home. If I'm at work, for instance, I may have to go all day without personal email. That's tough. I've been out of the country, as well, when it's gone down. Imagine going weeks or a month without personal email. On my last trip out of the country, I had to ask a neighbor if she could go reboot my server for me.
She would eventually get to our house in the next several days.
I still have my work email, but I don't use that for personal correspondence.
