Now if you multiply these hypothetical two or three weeks by the hourly rate of someone who can learn, you'll get the cost of replacing the author with another employee.
My point is that the cost could've been much smaller.
My point is that the cost could've been much smaller.
In summary: There is a "too much" and a "too few" when it comes to the number of tools used in a project. Where in that spectrum the OP is falling, we can't possibly know without knowing more details. Maybe the cost could have been smaller, maybe they hit an optimum and costs couldn't have been reduced by fewer tools (or more tools).
Still, bash and (most likely) sed could've been easily replaced with Python.