I don't understand your statement. Numpy has been ported on python 3 more than 18 months ago, and scipy followed quickly afterwards. Our download stats show rather little interest for python 3, BTW.
The numpy and scipy core may have been ported, but many of the Scikits (add on libraries to scipy), third party libraries and surrounding tools haven't. So most people will still go with python2 just in case they might need to use one of those tools or libraries later down the road.
You're severely underestimating the impact that the scientific computing community has over Python 3's slow adoption.