That’s exactly the thing? Why would you bother optimizing the code, looking for overallocations, leakage, tweak parameters, when you can just take a friendlier language for the same benefits.
I think the question is whether they significantly changed the architecture at the same time. For example, reading the description of the Python migration sounds like they applied a lot of experience which would have benefited any language, and micro-optimizations like what you described would have been a rounding error on those larger changes:
