Yup and a lot of that is the result of 8 years of work shopping. I also don't think it's fear. It's anger of over the failures of the system. Things learned from the ways in which Bernie and Trump harnessed social media.
As somebody who spent 15 years on the ground working political campaigns before hitting eject in 2020--- Bernie's campaign was one of a kind it it's ability to fuse justified rage with hope that the political process could bring change. It dwarfed the activism of Obama 08- which was much more superficial in its demands.
He had insanely high approval ratings with independents compared to Clinton. He had the youth working for him ala Obama. And he had the traditional non-voter. The thing he didn't have was the DNC diehard and that group grew more resentful over time towards him due to Clinton losing. But the reality is she won on the back of proud Democrats and he still made it close without almost any of those voters support. So the question is, do you think die hard Dems would have refused to support him had he been the nominee? Because if they had gotten behind him, he would have won. Point blank.