Sure, but so is Mojave. It'll be some years before Apple stops shipping security updates to older releases. Until then app vendors saying "don't upgrade macOS" is no different to Java developers saying "don't run this on Java 11 because it doesn't work yet" and we've seen plenty of that.

In fact, I'm guessing the pain of losing Java 8 will be too much for many organisations after so many years of stability and 9/10/11 breaking so much (current Gradle doesn't even work on Java 13!). Maintaining 8 will be a good business for a long time.