Obama has governed as a Third Way Democrat since he was elected. If you can point me to when Obama began governing as a left-wing progressive (oh how I salivate at the idea), please, let me know.
Additionally, as a Sanders supporter, the idea that Sanders’ (relative to what he expected) popularity is based upon some kind of foundation built by Obama is extremely humorous. Obama, though he has governed competently, has done little for left-wing initiatives. Unless you consider the ACA, undoubtedly the crowning achievement of his presidency, left wing. (hint: it’s not.)
When your magnum opus piece of legislation is about mild as you can get while still calling it “healthcare reform”, I find that claims of Obama being a socialist, leftwinger, etc are rather detached from the reality of the situation.
Especially since hardcore progressives like the OP thinks are everywhere are the ones who see the Democratic party leadership and rank and file as so corrupted and beholden by the 1% that they’d rather let the Republicans, whom they think are evil incarnate, into power and destroy the country (their beliefs, forcefully stated, remember) than vote for anybody not named Sanders.
Note that they have obvious counterparts on the other side of the aisle, who are a lot more obvious and who hold a LOT more power in this country. I think that’s significant.
You forgot Nixon’s EPA. But he was not a favorite of the right the way Goldwater was even in the early 1960s. He was a lot closer to the Rockefeller wing than the Goldwater wing.
Tea party inflexibility has worked pretty well for them if not for the country. And Obama’s flexibility did him little good. A bit more of LBJ grabbing them by the balls and letting their hearts and minds follow could help. Give them a chance to cooperate for a few months, and then lower the boom.