I disagree. They can do whatever they want because it's passion driven.

If people finds the new language wonderful they'll choose to spend their time there and to create their own community around it.

It's their free time and they have every right to choose how to spend it.

Also with RPC, the apache project arrow, etc... there'll always be people out there will bridge community.

Also is this really a problem? Programming language fragmentation? I've seen front end javascript frameworks fragmentation everywhere and they're fine with it. And the solution on the horizon are standardization such as web component (via w3c). These frameworks converge toward web component and now it's getting standardize. I'd argued that because of the fragmentation we actually know what we want to standardize and it also pushed for it.

If there weren't any fragmentation I'm not entirely sure if web component would ever be standardize.