I thought more about a higher level standard like adding Python, Lua or Qt to every installation by default. As some of those things are pretty heavy I doubt that it would be a wise choice to include them in POSIX.
Just imagine a world were you could simply write a small python script which would start a complete GUI application on different platforms without any additional installation procedures. To my knowledge that is not possible today. AFAIK the only way today is to bundle the dependencies, but that has a lot of negative effects.