gRPC is not necessarily the magical tool everyone would like to believe. It is mostly developed by Google with a lot of magic in it. For instance, in Python using gRPC is totally incompatible with multiprocessing (meaning: it will crash both processes) and has been for a year (1.4.0...1.8.4), because of all the C logic (and multiple threads) running behind it.

I for one am glad they didn't go towards custom protocols with single complex implementations, towards something that can be assembled easily from standard components.