Mathematical studies in the field of computer science have nothing to do with preparing students for writing mathematical software. It is to provide students with the tools needed for the study, design, and analysis of algorithms.

By using people who studied something more relevant to the type of specialized software being written, the specific needs and problems will be easier to capture, analyze and solve.

That may well be true, but that domain specific knowledge doesn't help the programmer/designer figure out algorithms appropriate to the task or to decide if certain approaches are even computationally feasible.