I can’t imagine why Cain would have been endorsing anybody “last time around”.. Not many people had even heard of Cain back then.
Cain had a radio show and had run for senate.
MANY people (including a HUGE fraction of FR) were supporting Romney as the better alternative to McCain.
Cain did what many did. He tried to pick the lesser evil.
That’s why he didn’t last long in the primary for POTUS in 2008. He endorsed Romney BEFORE Huck withdrew from the race if that tells you snything.