Bernie was the one, damnit.
Pretty crazy that his perceived age was one of the things that worked against him 2016 (he did look and sounded much older than anyone in the race) but he's as spry and sharp as ever in 2024, when his second term would have been over.
The fact that he was beaten pretty decisively in the primary is a testament to how elections are only partly based on policy and partly (mostly, imo) on personal image, likability, charisma, group identity, etc.
If it was just about policy, he would have been elected dictator-for-life 30 years ago. Even conservatives find a lot to agree with him on. But he wasn't well-known, is kinda creepy and old-looking, doesn't crack jokes, so he got beaten out by Hillary. And yeah, Democrats all dropping out in unison and backing her obviously helped, but it wasn't the only factor.