You can always use the c interface (which itself is weird, considering matlab's roots in fortran...)
The reason the C interface is weird is because MATLAB stores multidimensional arrays in column-major order, like Fortran. C, on the other hand, uses row-major order. However, if you work with linear algebra, then you'll appreciate the column-major layout, because it coincides with the order returned by the vec operator (which is used all the time in computational linear algebra, and stacks the columns of a matrix).
but then you'd have to learn c. Matlab is a tool for physicists and engineers, not computer scientists. They don't necessarily want to take the time to learn c, or they'd have done that. Some do, anyway, of course, but usually what they produce will be one off functions for a specific goal, not entire libraries suitable for sharing.
I work with digital signal processing and use MATLAB almost on a daily basis. The reason DSP engineers use MATLAB is not because they don't know or don't want to know C. In fact, a good DSP engineer must be very competent at writing clear and efficient C code, because that's what he needs to actually implement algorithms on hardware. Modern high performance DSPs are so complex that coding things in assembly is completely out of the question.
The reason MATLAB is so valuable is that it allows one to prototype things extremely fast with minimal performance loss (if you know what you're doing). Of course you won't have a MATLAB environment running on a DSP, so you'll eventually have to write the C code. But since most of my time is spent developing algorithms instead of actually implementing them, MATLAB lets me be much more productive.