No Bernie Sanders did not run an "amazing" campaign. He did not "change everything". He ran a terrible campaign against a ridiculously weak candidate. And he never managed to break through past his core base of the white left and students dumb enough to be influenced by social media. These were his bases. They are why he lost every state with a large minority population including California.
And no, Elizabeth Warren wouldn't have done much better. Neither would Hillary without Bill.
But Bernie's campaign was spectacularly clueless. Like much of the left, Bernie assumed that all he had to do was go leftward on the causes that specific minorities were supposed to care about.
He went more pro-crime than Hillary, yet black voters would still rather vote for a KKK robe on a stick than for him. He invoked Caesar Chavez throughout California and still lost.
Despite his supposed civil rights work, Bernie Sanders did not understand minority voters. His only appeal was to the left and that wasn't even enough to win the Democratic nomination.
Bernie voters can complain that the system was rigged. And obviously. Democrats rig everything. But Bernie Sanders still lost because he was a terrible candidate whose appeal was limited to the fringe fanatics who screeched at his rallies and to the remainder non-Republican white population in overall white red states. Bernie claims that as a moral victory. It's not. It's a joke. And so is he.