Just a brief follow-up. It seems that, in order to avoid getting an error when you instantiate the window, it is necessary to instantiate the vtkWin32OpenGLRenderWindow directly:
from vtkmodules.vtkRenderingOpenGL2 import vtkWin32OpenGLRenderWindow
win = vtkWin32OpenGLRenderWindow()
hasOpenGL = win.SupportsOpenGL()
Otherwise, the object factory mechanism that I mentioned earlier will raise errors while trying to decide what kind of window to instantiate.