Maybe. but actually what's important is investment cost versus the ratio of supply vs demand.
There are lots of Java jobs, yes, but there are also lots of Java programmers too. I'm a python dev (now) and while I have to search a little longer for jobs, I get good pay still, since I'm also rarer.
I think that what is important is how easy code is to maintain and how easy it is to move from 60 modules to 6000 modules (and beyond). Running a big code base in PHP is very, very difficult (I have done this, it was not a good experience) running a big code base in Java is better (I have done this too, it wasn't that great but some of the information hiding and abstractions in Java seemed to help partition the issues from one another). I have never run a large code base over a number of years in Python, I expect it's rather like doing things in Java. I feel strongly that if I had to run a large Julia code base (in about 2 years when it goes gold) then things might be much improved and much less make work might arise.
There are lots of Java jobs, yes, but there are also lots of Java programmers too. I'm a python dev (now) and while I have to search a little longer for jobs, I get good pay still, since I'm also rarer.