The fact is, if Newt dropped out, I wouldn’t vote for either Santorum or Romney in the primary, and I believe many Newt voters feel the same way, so your assumption that those votes would go to Santorum, are, I believe, misplaced.
Maybe those who worship him like some sort of God might not, and we see those crazies with all types of candidates, but most would do the right thing and vote for the remaining Conservative in the race.