It seems to be trivial productivity. People like to say they've contributed and it's easier to port trivial libraries to new frameworks. I'm amazed everytime I see XYZ ported to framework de jour so celebrated.
Copying is the foundational intelectual activity. Arguably copying enables natural language and culture. The world wide human network is engaged in a large scale genetic algorithm founded on copying. Porting successful features serves as an effective filter for bad ideas. Good ideas thrive and are copied everywhere, bad ideas get few copies and eventually die in obscurity.
