You tried what? I don't think Obama claimed he would instigate medicare for all, just health care reform (which he did and the ACA was). And considering that Republicans won back Congress by screaming that Obama was a communist/socialist that was going to raise your taxes and institute death squads for his socialized health care, not sure how you can claim the rest with a straight face. The ACA doomed them because Americans chose to believe lies and bullshit, and medicare for all likely would have lost Obama a second term, and would have gotten Republican dominance and they would have likely torn it to pieces immediately.
What happened is Democrats sought a compromise on health care to get Republicans on board. Republicans decided to just go ahead go completely insane, just started spouting lies and getting extremist, which worked because Americans are often idiots that will listen to crazy people spouting bullshit instead of trying to be rational. But given time, they will see through the lies.
Its only after all the evidence that, while flawed, the ACA was helping tens of millions of Americans, and Republicans showing that they were just lying about everything they were saying with regards to health care (all the lies about the ACA, that they had a plan and weren't just trying to destroy the ACA because they hated Obama and Democrats, that they aren't despicable assholes who would gladly tell you to fuck off and die so that you don't cost them a penny more, how out of touch they were saying people were buying iPhones instead of health care while ignoring that health care for a single month costs many families more than iPhones so even if they didn't buy iPhones they still would struggle to afford health care; I'm sure I'm leaving out a hell of a lot too) and trying to run and hide while they worked to fuck millions of Americans over, that Americans got good and mad.