I want to clarify that the proposed change would break:

operator.attrgetter(foo)(bar) == getattr(bar, foo)

Which is the documented intent of the operator module: "This module
exports a set of functions implemented in C corresponding to the
intrinsic operators of Python."

Unless, you are proposing getattr grow this functionality as well. IOW,
should PyObject_GetAttr* perform this recursion? If so, should
PyObject_HasAttr*, PyObject_DelAttr*, PyObject_SetAttr* do this as well?
At the moment, it is possible to have foo's (as in above) that contain
dots despite the inability to spell that in python's dereferencing
syntax. However, I don't know that anybody does that.