"Everybody who supports single-payer health care says, ‘Look at all this money we would be saving from insurance and paperwork.’ That represents one million, two million, three million jobs [filled by] people who are working at Blue Cross Blue Shield or Kaiser or other places. What are we doing with them? Where are we employing them?"
So it seems that Obama didn't pursue a single-payer system because keeping 2-3 million "bullshit" jobs was more important than efficiency in the health care system, or at least it was part of his reasoning.