[hiAndrewQuinn]

Java's version history crawled along at a snail's pace until Java 10, when they switched from a feature-based to a time-based release schedule. The release cycle has been pretty quick after that, since that happened only after 2017 or so.

That, combined with some pretty large changes in the underlying security model, mean that a lot of places have been stuck on Java 8 for a real long time. It's much harder to move from Java 8 to Java 9/10/11 in a lot of places than it is to then go from 9/10/11 to 17, for multiple overlapping tech debt cleanup reasons.