For some people, email is not a big part of their lives, and it's probably fine to have a free service. But I'd argue almost anyone for whom email is a daily necessity, you should be paying for a certain quality of service. I mean, your email is the core of your online identity, and if it vanishes, such as the dozens of stories we've heard of Google terminating people's account without warning, it can be devastating to put everything back together.
> For some people, email is not a big part of their lives
Email is a big part of everyone's lives, who made an online account somewhere. Not to mention if they paired real identity and/or money to those accounts.