I would argue that his contributions were central to the birth of rigorous machine learning (the non deep learning kind) as a field of its own with a focus that's different from that of statistics.

One quantitative test I can suggest -- one can count the number of occurrences of the word 'statistics' in the journals and conferences he has published and compare that with the number of publications he has authored. My sense is that it will be close to 0 and getting closer (if not already there yet).