From languages I would have thought that golang and rust would make larger inroads, but maybe that is still to come.
Honorable mention would be Java an in particular "agent"-frameworks. Thought it would be the future of automation. Perhaps people actually use it, I just haven't seen it implemented anywhere.
I had a similar thought. Obviously Java "the language" is, indeed, widely used and did become "the future"... but certain parts of the broader Java vision didn't quite pan out: the "mobile code" and "agents" stuff in particular. "Java in the browser" was big for a time, but ultimately faded. Which I actually find quite disappointing on many levels.
All of that said, I don't think it's out of the realm of possibility that some of the "agent framework" stuff comes back into vogue at some point - at least in specific niche domains - although it may or may not involve Java.
[1]: https://en.wikipedia.org/wiki/OpenSocial
[2]: http://w3c.github.io/packaged-webapps/api/Overview.html
On the other hand I didn't exapct Go to go anywhere. I remember briefly paltong with it a few years before it became popular and kinda just set it aside because I thought it was just some random toy language from Google.
Old school Enyo is hard to work with these days and there are many many dead ends and the community is majorly lacking but for a sheer JavaScript framework it’s one of the originals and the best.