[klank]

In my personal experience, while the experience you're describing is frustrating, it didn't feel connected. I don't see a connection to prevalence of HTML being a driving factor. Even when I was using pine I'd use irc or aim if available.

For me, it was simply the lack of adoption of messaging options that made email the default tool. Once cell phones came along and people got accustomed to instant quick messaging that was generally ubiquitous, email was out, whether you were using pine, outlook, or something in between.