MATLAB toolboxes are simply awesome for users, even though they are expensive. We hope that if enough people find julia useful, many such libraries will be built. Having written a ton of mex and matlab stuff, and a lot of julia libraries, I find that julia is nicer to use personally - but of course I am biased. :-)

I do believe that open source + good compiler + simple C/Fortran calling interface will lead to others being able to write toolboxes in julia itself and plugin libraries when needed.