i'd guess that given the antibiotics, better nutrition, wide availability of warm clothes/shoes, etc. natural selection pressure for higher temperature has nat

i'd guess that given the antibiotics, better nutrition, wide availability of warm clothes/shoes, etc. natural selection pressure for higher temperature has naturally decreased (in such historically short period that decrease mostly manifested itself in much lower child mortality). People also became bigger during the last century which results in better thermodynamics, ie. surface/volume ratio, thus less need for burning of the internal fuel, i.e metabolic rate can be lower. Compare - elephant's 96.6 vs. cat's 101.5 body temp.