Superdelegates will not be a factor this time. That is what Bernie supporters were sulking over.
So if Biden gets the majority, it will be recognized that is what the voters truly wanted and they cannot deny that.
I know some Bernie fans, granted not a statistically valid sampling, who all believe that the proverbial fix is in and that Biden will get the nod... they are at best pessimistically hopeful that they are wrong.
As to Bernie... he never truly backed Hillary's win, and the numbers put her in the lead regardless of the Super Delegates. Bernie acted like a old slighted curmudgeon before and there is not reason to think he would do otherwise this time.
Regardless, if Bernie loses, I believe many of his followers will stay home in big enough numbers for Biden to lose. Biden might win the popular vote, but not the EC.
If Bernie wins, I don't think he will bring any moderate Republicans or Conservatives. Independents might be a more or less split. In addition, a Bernie win might actually motivate moderate Democrats to not vote for a presidential candidate... the "I don't like Trump, but just can't bring myself to vote for a fringe socialist who has never actually been a Democrat" position. A Bernie win would definitely motivate moderate Republicans & Conservatives to vote against him; i.e. for Trump.
>>> Americans just don't like "socialism", it is a dirty word. <<<
(Side note: Yes, it is true the most Americans don't even know what the word means, and many don't even disagree with socialist ideals. But they hate the word, which is enough for most Americans. Catch words and phrases matter to Americans more that facts.)
In addition, Trump presently has the economy going for him, and if it tanks that won't happen fast enough for him to be damaged.
At best Bernie would win the popular vote and lose the EC... at best.
Just my opinion.
But I like your optimism... hopefully you are right.