[StopDisinfo910]

This is a circular self-defeating reasoning.

If you want to push a new technology, you need to start somewhere. That's exactly what's happening with JMAP. It was created by Fastmail to use as a bridge between their servers and their own apps a case for which popularity doesn't matter. It's basically a modern vendor proprietary protocol but done in the open.

From there, support is only a matter of someone being interested enough to implement it and manifestly it's working. There are now three servers (Apache James, Cyrus and Stalwart) and some clients.