Google hires devs to develop similar libraries... to power their machine learning efforts. There is tons of numerical work in finance, too. I don't think the money is to be made by selling copies of a Matlab-like piece of software, but in the application of the tools.
I haven't used Grumpy at all, and unless it starts supporting C extension modules like NumPy I doubt I ever will. Google's numerical computing / machine learning stack (e.g., TensorFlow) is based on Python/C++.
Ken Thompson didn't (still doesn't ?) have commit access because he hasn't been vetted by Google as a competent C programmer. I don't think Google is going to relax its hiring policies no matter who you are.
