I've never really understood why socially conservative and religiously minded voters (who obviously make up a big segment of the GOP primary electorate these days) didn't give Santorum a look in this year - sure, he doesn't have much money backing him, but he had the name recognition from 2012, plenty of congressional experience and is pretty articulate and authentic. Meh, guess it shows how much I know.
I'm guessing two main reasons:
1) They never really liked Santorum much to begin with, they just didn't like Romney.
2) Why settle for the old (Huckabee, Santorum) when you can have the new and shiny (Carson, Cruz?)