It came from the same source code as Matlab, shares almost identical syntax and looks and feels just like a 1990s version of Matlab. It is far older and more mature than the other alternatives (octave, sage, freemat, numpy..) and unlike most alternatives, it has a dedicated (and paid) development team. It also has widespread use in Europe and Asia.

It should be the top alternative to Matlab but it has almost no visibility in the US. Does anybody understand why?