Java nowadays is mostly used for business applications, where developer productivity is more important than runtime performance. Java being memory safe is a huge part of that, which is the JVM platform. Java the language had the major feature of being superficially similar to C++, that helped take over the business market but is now no longer relevant. When Java was first marketed as a business application language there were few competitors. Nowadays there are, but nowadays the major reason to choose Java is because it is entrenched and good enough.

However all the Java shops I hear about are also looking into Kotlin at some level of adoption. From all the new JVM languages Kotlin integrates the best with the existing Java environment and for displacing a language in an existing niche an easy upgrade path is the most important. So I think Kotlin will become an important language in the JVM ecosystem, it will just take a long time because these types of businesses are conservative in their tech choices.