"Barack Obama, after all, has spent much of his presidency trying to build a grass-roots movement to force change on Washington that he couldn’t achieve from the White House."

I never saw any evidence of such a grass-roots movement. What I've read is that Obama did no such thing, that he built up a large database of supporters during his campaigns and then didn't ask the people in it to do anything. The movement I saw was Occupy and a whole lot of activists who have labored for many years to get this country to move, and recently the Bernie Sanders campaign. 

The neoliberals who elected Bill Clinton and Obama, and have picked Hillary Clinton as the Democratic candidate, strike me as middle-class people reasonably satisfied with their lot who are unlikely to move anything.