> overwhelmingly driven by existing large enterprise codebases
That happens with all mainstream languages, but it's a feedback cycle. The more popular a language is (in large enterprise codebases), the more it will get used in new projects, for obvious reasons. People want to get shit done and to have good ROI and maintenance costs. Therefore, the availability of documentation, tooling, libraries, and developers helps, in large and small projects alike.
And yes, Java is quite fresh, IMO.
It seems to me the more popular a language, the more poorly written libraries are found in it, which soon starts to draw people away from what is popular to a new language that has a limited library ecosystem thinking they can fix the mistakes they saw last time and make a name for themselves in the process. Lather, rinse, repeat.
We've had a potential client ask for a PoC in Java 8, to integrate with their current system... But yeah, our product is deployed with Java 11 and since some dependencies have issues with 18, we'll likely stay that way for a few more years
Nearly all companies I worked for were developing new systems, tools, etc. Rarely I was doing maintenance on "existing larger enterprise systems".