It does not seem credible that Obama was unaware that failure was likely. And if he really was unaware, the implications are extremely unflattering. Either he failed abjectly to ask the right questions of a staff that was also derelict in informing him, or else he asked the right questions and his staff misled him. What the Times story confirms is that the launch of Healthcare.gov wasn't the sort of failure that reasonable actors could have failed to anticipate beforehand.As it happens I'm reading (struggling through actually) a recent biography of John Kenneth Galbraith. He was an adviser to JFK while serving as ambassador to India in 1961-2, had his own back channel to the President, and was audacious in his infighting (like stealing a highly classified copy of a report to which he'd been denied access off the desk of the NSC type, while the NSC guy's attention was on a phone call, then writing a preemptive counterblast for JFK).
It's a dense and scholarly effort, which goes rather broadly into the infighting over whether and how strongly to intervene in Vietnam. And based on the narrative, JFK's decisions were sometimes/often evaded and ignored by the NSC/State/DOD figures. The bottomline: not only did the flow of decisions from the President to the bureaucracy get interrupted, the flow of information from the bureaucracy to the President was uneven and incomplete. JFK was smart enough, probably having read Neustadt's book on Presidential Power, to have multiple sources; BHO may not have been that smart.