Hillary Clinton is a great woman who has done a lot of good in this world, but matured into and mastered a political landscape that underwent massive change as she ran for president. So all the things she had to do to overcome the still ingrained sexism in our political system, like appearing tough by being somewhat hawkish and not taking big swings because you could be accused of being emotional, etc...,
just didn't work anymore. If she could have just let her guard down and dropped the politician speak and dumped the political consultants I think she would have beaten Trump. And if she had been able to get a majority in the Congress I'm convinced she would have signed Medicare For All into law. She just wasn't convinced she could spend her own political capital to push for it and be successful.
For decades, people became more and more disenchanted with politicians because of their ever calculating, triangulating speech which comes off as manipulative and inauthentic. And then when a rich opinionated idiot with no filter came along many people conflated his audacity and loutish behavior with authenticity.
A growing number of voters are becoming more sophisticated and the old ways don't cut it anymore. The El Sayed win is a great example of this. In order to win today you need to demonstrate authenticity, expertise and enthusiasm. Clinton had the expertise and the enthusiasm, but she always came off as cold, even though she's a lovely person. It's interesting that Bill seems more authentic and approachable, but he's the real bastard in that couple.