In the last paragraph you closed with “Was plain text awesome all along?” The answer, resoundingly appears to be “yes.”

While it is nice to have a rich graphical experience in one’s in box, there are several problems with multimedia content:

It reduces the number of mail clients capable of rendering a document correctly, reducing the potential audience.
It substantially increases the amount of data you must transmit. A simple text message of 20KB in length might become 500-600KB or more after HTML and images are added to it. This greatly increases the cost of mail transport.
It decreases the likelihood of a message being successfully delivered. Aside issues with transport—e.g., the longer the message the more likely it is to be interrupted—including rich content such as HTML and images is more likely to cause mail to be tagged as spam.

While text will never be as pretty as HTML, it does have the advantage of being ubiquitous and allows a wider range of people to share a compelling experience, even if it is one set in a 10-point Courier New typeface.

Regards,

Aryeh Goretsky