Because the RINO Establishment likes everything status quo. Besides, IA has only picked the eventual nominee 2 times in the last 6 elections. To its credit, it chose Santorum over Zero’s Ringer, Willard in 2012. Even if Dr. Carson narrowly beats Trump there, Trump is ahead virtually everywhere else.
I say shake it up. A new state every time. Based on population, or admission into the Union, or a lottery each cycle.