That article has some flaws, it for example does not consider that during BoB Spitfires more often engage LW fighters while Hurricanes went after the bombers.
The numbers of available planes during BoB was not the real issue either, RAF had more fighters at the end of the fights than the beginning. Replacing the losses of pilots was a bigger problem.
The idea of only having Hurricanes instead of the spitfire might have worked in 1940 but the Hurricane was still obsolene and with new 109 versions (and the 190) the Hurricane would quickly have lost is effectivity in combat. In the early years of the war it was few planes besides the spitfire that could compete w the German fighters. RAF were able to counter the 190 w the introduction of the spit IX and i don't see that there was that many other planes that could have done it in so short time.