Programmers would create a new language when there is a fundamental change in hardware architecture such that the assumptions underlying the old programming languages no longer apply. Java is probably a poor choice for writing software in which most computation happens on GPUs. But I agree that someone (or something) will still be using Java to write new line-of-business applications in 50 years.
Mostly a tongue in cheek reply, but you might be interested in TornadoVM.
(Nonetheless, I agree with you)