The current state of email clients is such that responsive email is considered one of the most difficult tasks in web-development. It’s time to force the hand of email client developers.
In 2001 Jeffrey Zeldman wrote:
[Web] standards have been around for years. Browsers that support them have been around for six months to a year. If not now, when?
It typically takes 18 months or longer for web users to upgrade their browsers. Many still use browsers, like Netscape 4, that date back to 1997. These folks will only upgrade if we give them a reason to do so.
To hell with bad browsers, A List Apart