I really do not think that Wilkie is a valid comparison, because the Oligarchy running the GOP are not the same as those that were running it in 1940. After 71 years, no political movement is going to be the same. If there were still liberal Republicans like Wilkie, they might have a chance of winning the presidency. Huntsman is the absolute best candidate the GOP could nominate, but it looks like he is not going to make it.
Wilkie worked with FDR during the war and apparently Dewey was more liked by the GOP then.
Cain does not occupy the same place in the GOP now that Wilkie did in 1939.
I do not see Cain getting the nomination. If he were to do so, I doubt that he would be elected.
Time will tell.