To a first-order approximation, engineering is about minimizing costs, and a large fraction of the cost of creating and running a fab is the cost of the time of

To a first-order approximation, engineering is about minimizing costs, and a large fraction of the cost of creating and running a fab is the cost of the time of the employees able to understand things from first principles. So, just because they decided to avoid that cost doesn't mean they are unable to redesign the pipes from first principles.