Right, they could have changed their votes, but they didn't vote at all according to that graph.
Interesting data from exit polls (via 538) - looks like 2016 Bernie voters aren't really showing up? He got 60% of the vote last time, so like half of his voters just didn't bother coming out. Did they think it was all locked up or something? Very strange.
www.resetera.com
Last post I'm responding to about this because literally nobody is understanding what I'm saying, or what the original poster was even mentioning it for. Obviously with more choices the votes and percentages will be split more. That's not what the graph is showing, it's from an exit polling question regarding who the voter supported in 2016. If 100% of Sanders supporters from 2016 voted in the 2020 primary,
regardless of who they voted for this time, Sanders would have a minimum of 60% on that graph. But he only has 30% to Clinton's 50%. Therefore many 2016 Sanders voters didn't show up for this primary.
So yeah, I'm done responding about this because I can't explain it any better. And again, this isn't even a bad thing (for Sanders) because it means Sanders has more supporters that just didn't vote today.