McCain's was moderates & independents, whereas Romney's was basically just middle- & upper-class Reagan conservatives & professionals in the suburbs.
Those were the groups that McCain and Romney targeted. But both failed.
In 2008, Obama won moderates 60-39%. (In comparison, Bush lost them by just 50-48%). Romney in 2012 didn’t win anything outside of the south and the Heartland, except Alaska? So I don’t think he won the Reagan Democrats and the professionals in the suburbs.
We're discussing their bases in the 2008 GOP primary, not either of their general elections.