Just use Arrow http://crsmithdev.com/arrow/ everywhere, all the time(s). Now your date/time problems are solved.
This means Python and Ruby aren't as much of a first choice as they used to be, even if they're arguably a lot faster for getting MVPs out.
Which is precisely why all of my new code targets Python 3 and I use PEP 484, and before that I always had type information in my docstrings. There's some places where duck-typing makes sense, but a lot of times I'm really just doing things like I would in a statically typed language so I just type the crap out of everything and run MyPy against it.
Unfortunately the runtime itself doesn't benefit at all from the type information, but I know I any of my .Net-centric colleagues can easily inherit any of the Python code I've written and be able to read it without much headache - without having to intuit what magic goes on behind the scenes, especially with things like the Pyramid request/context objects.
Which is why numpy and scipy are so full-featured and pretty damn fast.
To say NumPy or SciPy is just the sum of the libraries it uses is a bit like calling MATLAB a fancy interface for LAPACK. That really was what MATLAB was intended to be originally, but to reduce it to that is missing the appeal. As somebody who absolutely loathes MATLAB, even I wouldn't think that is fair.
The major feature of Python for me is that all its various open source modules for anything n-dimensional (matrices, image processing, GIS, machine learning, etc etc) all use the same data structure: the Numpy array. It's basically part of the standard library that is developed outside of it for pragmatic reasons. And with the speed of Fortran array operations.
That's something that only Matlab really has as well, but Python is much better in other aspects.
I've been a Pythonista for over a decade, and the API scene isn't quite as utopian as you describe. Date/time handling in particular is a really poorly handled area, but there's quite a few out there.
That said, in general I agree the 'batteries included' approach is good, and the libraries _tend_ to be easy to use for most tasks. Compared to most Java libraries, it's a breath of fresh air.