Comment by legacynl

I don't know what you're talking about. As you said mail hasn't changed that much, I've been using Thunderbird all that time, and except for an improved default theme, they honestly haven't changed much about their core features. In that time I was able to remove several plugins that have been added to core thunderbird, like threaded conversations, google calendar and contact support.

I think the biggest change has been that people nowadays expect more from a regular email client.