Earlier quoted context omitted.
I think it's more that existing projects are in Java, so I have experience in Java, Java works, so why learn something else? Just start the next project in Java and it'll just work.
That would imply that the world moved from Java to Node.js / Go / Python just because they are cool new technologies.
And, yes, that's often the reason parts of the world move to other things. Hopefully, someone saw an actual problem with the stack they were using, saw a solution elsewhere and moved. However, anecdotally, I often see people deciding emotionally that the Hip Cool New Thing is The Right Way To Go and that's what they use ... and then discover the warts are bigger, or the problems aren't actually solved, or the only thing different is the vocabulary.