Yet, the replacement for MatLab appears, at least to me, to be Python. The abundance of resources due to its general purposeness swamps Octave/MatLab's niche tailoring. Python is a mire flexible tool for STEM because it supports a broader array of applications.
Python does not replace the Matlab language itself. For as long as we have Matlab code, we will need Octave.
My hope is to make Octave as obsolete as Matlab itself, but so far neither is. Matlab is huge and Python has not unthroned it. It will take a combined effort to do so. Octave is but another contributor to this effort.
In that sense Linux doesn't replace other Operating Systems. But of course it does and that's the sense in which I used the word "replace". As with Windows and Linux, Python is used in lieu of MatLab frequently for new applications as the total number of applications grows.
Programming languages are not quite like operating systems (and even Linux has Wine). When you have a large codebase written in some language, you can't just easily throw it out and rewrite the whole thing in another language. Programming languages never really die out: COBOL is still used these days.
There is a lot of Matlab code out there, and it needs something to run in other than Matlab. That's why Octave is still important.
I didn't suggest Octave wasn't important as an alternative for MatLab. I stated my opinion that Python appears to be replacing MatLab in the niches where it dominates. If there is a new project, Python is likely to be a competitive alternative to MatLab or Octave.
To a first approximation based upon the number of times I have heard of Julia relative to the number of times I have heard of Python: nope, never heard of it.
Julia looks like a fine language. Just not being Python is enough for me to assume it's better than Python.
But I'm describing is's not ought's. If I was in charge of the ought's third graders would be learning J. I'm not. They aren't.
Python is the clear winner. There are many other useful alternatives - another commenter mentioned Julia - but part of the reason Python wins is because it is so pervasive. It is easy to find examples and help online, and for scientists, getting results is the most important part, so anything to speed development is important.
Yet, the replacement for MatLab appears, at least to me, to be Python. The abundance of resources due to its general purposeness swamps Octave/MatLab's niche tailoring. Python is a mire flexible tool for STEM because it supports a broader array of applications.