You can't really compare MATLAB and Mathematica. Mathematica excels at symbolic computation whereas MATLAB is primarily geared towards numerical analysis and scientific computing. You could code numerical things in Mathematica, but you'll get poor performance compared to MATLAB. Similarly, MATLAB does have a symbolic toolbox, but it pales in comparison to the extensiveness of Mathematica. Numerical and scientific computing work is generally more useful in industry than anything you would do with symbolic computation (e.g. you wouldn't analytically solve a sophisticated PDE so you would use numerics), so that explains why MATLAB seems more prevalent. As for your first question, I would say that Mathematica definitely has a lot of power built in. I know a few researchers (myself included) who have used Mathematica in some really cool ways only knowing the basics, which I think is a huge audience for Wolfram. With that said, there are definitely many power users who are probably doing greater things with the language.