Well, apart from the incredible standard library, there is an interesting programming language.
What I think is missing is a stripped down open source implementation / interpreter. What Gnu Octave is to Matlab. That stripped down variant could or could not share some code with the proprietary implementation (realistically, Wolfram would need to open some parts of their code).
I think octave is invaluable for helping Mathworks: Professional users will almost surely buy a license, but a lot of matlab/octave code can be run and hacked on without a mathworks license (albeit slower, and missing a lot of cool features).
The way it is now, all code written by scientists in the Wolfram language is essentially hostage to Wolfram. An octave equivalent would permit people to trust that they continue to meaningfully own their own code.
It is super unlikely that a stripped down slow but open implementation would ever improve to the point of being a meaningful competitor: The thing Wolfram has built is impossible to replicate in the open source world.
Sure, there are other computer algebra systems and other frameworks / languages, but these have very different strengths and weaknesses that make them appropriate for different niches. E.g. sage permits seamless interfacing with the entire python ecosystem (never write a parser or networking code in mathematica! Everybody and his dog publishes python bindings to their C++ libraries nowadays). Or julia with its multiple dispatch and late-AOT/JIT approach that permits permits to write super fast dynamic code that is Fortran / C / C++ level fast.
What I think is missing is a stripped down open source implementation / interpreter. What Gnu Octave is to Matlab. That stripped down variant could or could not share some code with the proprietary implementation (realistically, Wolfram would need to open some parts of their code).
I think octave is invaluable for helping Mathworks: Professional users will almost surely buy a license, but a lot of matlab/octave code can be run and hacked on without a mathworks license (albeit slower, and missing a lot of cool features).
The way it is now, all code written by scientists in the Wolfram language is essentially hostage to Wolfram. An octave equivalent would permit people to trust that they continue to meaningfully own their own code.
It is super unlikely that a stripped down slow but open implementation would ever improve to the point of being a meaningful competitor: The thing Wolfram has built is impossible to replicate in the open source world.
Sure, there are other computer algebra systems and other frameworks / languages, but these have very different strengths and weaknesses that make them appropriate for different niches. E.g. sage permits seamless interfacing with the entire python ecosystem (never write a parser or networking code in mathematica! Everybody and his dog publishes python bindings to their C++ libraries nowadays). Or julia with its multiple dispatch and late-AOT/JIT approach that permits permits to write super fast dynamic code that is Fortran / C / C++ level fast.