Hmmmm … let’s take it point by point.
“it is still important to note that the DNC did not actually rig the primaries” — the DNC didn’t rig the voting, but helped a candidate’s fund raising, actively supported a candidate, provided that candidate with advance knowledge on questions asked in debates and so on.
“Trump’s winning margin was less than the number of Sanders primary voters” — yes, Hillary would’ve won the primaries .anyway and likely would’ve lost the main anyway. But this is the most pointless point anyway. The take here is that the whole affair was moot but going on Hillary it also means she didn’t have to use the DNC the way she did, basically throwing any measure of Democracy out the window. And Bernie? “Yeah, my opponent has no grasp on what democracy means but please vote for her”.
“Bernie’s revolutionary platform is no longer unique to him” — so is unicity the only thing to make a candidate? He’s the one that has actively pursued them, got legislation in and through his previous campaign got them mainstream. But there’s another side here. Except Warren, nobody comes close his platform. Many promote an idea or two that are similar but that won’t be enough to a base sliding left.
“many of her voters […] now have plenty of reasons not to like him” — that’s assuming the base is some sort of immutable mass, despite polls showing the Democratic base shifting to the left. Unless that’s simply because of younger people getting voting rights, it means that the base has shifted. Bernie’s base may be there but there’s no Clinton-like opponent. In the face of a left-shift, most of the others are simply not leftist enough for the upcoming wave of progressivism.