At the time, the administration had the choice of pursuing health care reform or immigration reform. Had they chosen the latter, it also would have been criticized as socialist legislation, even though the Chamber of Commerce was for it.
But since you brought up the ACA, I was chatting with a friend who is a doc the other day. She's not an ACA fan because of the restrictions and agrees with me that the Dems belief that the mandate would get enough young folks to sign up was naive at best. She said docs will be happier with the ACA repeal in terms of their practice but recognizes that we'll again have a ton of people not covered, and the Pub plan will be a failure. And after that, she is hopeful we'll end up with some type of single payer plan - probably more of a single payer plus plan where co-pays essentially mean people with means will get more care than lower income folks.