The scientific community is not that interested in merging into the stdlib.

Also, the main point of this is to allow for different async libs to find some common ground to stop the madness of having twisted-specific, tornado-specific, etc... The scientific community does not have this pb because everybody uses numpy.

The scientific features are only of interest to the (drum roll) scientific community.

Async interests potentially everybody, including the server guys, the backend guys AND the scientific community.

Not to mention that this is a few contained classes, whereas the scientific stuff is tons and tons of code to be included into Python, including lots of Fortran and C, that would more than triple the size of the standard library.

Lastly, node.js? Lots of languages have a good story for async, from C# and Scala, to Go and Rust...

Guido lets Enthought, Continuum and programmers of that ilk take care of the science side of Python.

I think because scientific features are not fundamental tools of expression, while he is working a language that is trying to be the foundation (most general) for the more specific libraries or tools.