Not to discredit what you are saying or how amazing the success of human ingenuity has been, FDR might not have had polio. Modern research seems to imply that he actually had Guillian-Barre Syndrome. The Roosevelt family wouldn't let them exhume his body, so we probably will never know. Either way, there was no cure in FDR's life and his treatment would largely have been the same. Just food for thought!
https://en.wikipedia.org/wiki/Franklin_D._Roosevelt%27s_para...