Certainly one driver of statism is arrogance -- the technocratic belief that one's intellectual capacity and decision-making ability is superior to that of the masses, and therefore should be substituted (via authoritarian control) for that of the masses. This was clearly the driver of statism in the early to mid-century. Its what caused FDR to be so enamored of Mussolini-stype fascism. A few smart people making the trains run on time.
But I am starting to wonder if there isn't a second driver of statism that comes from the opposite direction -- projecting one's own weaknesses on the rest of humanity and, assuming they share these weaknesses, using this assumption as a reason for mommy-state controls. This latter reasoning came through in this article summary in my feed reader from the Arizona Republic:
Lamenting his first teenage cigarette, President Barack Obama ruefully admitted on Monday that he's spent his adult life fighting the habit. Then he signed the nation's toughest anti-smoking law, aiming to keep thousands of other teens from getting hooked.