LOL. They had to drop the public option just to get the Democrats to in the Senate to vote for the bill. Single payer would not have gotten anywhere.
Never mind that it's the Congress that passes bills, not the President.
Obama could not have introduced Single Payer. There is just no political will in the US to do that. None. The medical industry is in one form or another is 1/6th of the US economy, you can't change that overnight.
Because Joe Lieberman refused to support it. Without his support there was no chance of single payer passing.
I think there is a good point here, though. By compromising early and relatively privately, it never became a real topic of conversation amongst normal every day Americans. Maybe if Obama had come out as a fire-breathing liberal supporting single payer ("Medicare for all!") and used his bully pulpit to make everybody hear about it, we could have had a better discussion. Sure, it might have kept the ACA from happening, but maybe in the long run it would have given us better results.
Anytime you make a compromise, there's always the possibility that maybe you could have held out for more.