Americans voted for Biden because the primary system heavily favored Biden and Americans were told Biden was "more electable" than Bernie, even though every one of Bernie's policies and his messaging polled better.

If the DNC didn't put their thumbs on the scale, Bernie would have won in 2016 (or 2020), and guaranteed a democratic victory in the next election because nobody receiving free healthcare is going to vote to go back to the current system.

Bernie isn't radical, he's a social democrat, he just looks radical because the democrats are right of George W Bush right now.