The previous posts here touch all this subjects:
A. The documentation explicitly says: "When the pool object is garbage collected terminate() will be called immediately." (Happened till a code refactor 9 years ago introduced this bug).

B. Large amount of code was developed for this technique:
https://github.com/python/cpython/blob/master/Lib/multiprocessing/util.py#L147 (Till the end of the file almost)

C. The reason I opened this bug was because I was called to see why a long running process crashes after a while, and found out it leaked tons of subprocesses / pool._cache memory.

D. The quoted code, will currently simply leak each invocation lots of subprocesses... 

I too, think we should push for the said fix.