I think you are right, Greger, but only on the winning part. A large part of the Democratic Party has moved enough left to sway Congress in that direction. This is mostly in reaction to Trump, not because they support Bernie. He's only pulling about 27% of the votes in California, probably the most progressive state there is.

So don't expect a single-payer tsunami, but do expect ACA's problems to be fixed and a public option added.
Don't expect $15 per hour minimum wage, but maybe we get $12.
More states lowering state college and university tuition. More selective occupation student debt forgiveness.
More Solar rebates and fewer coal power plants.
Higher top tax rates for the rich.

You don't always get what you want, but sometimes you get what you need.