But there's a huge difference between a moderate progressive who's always been a Democrat and a centrist who used to be a Republican.
And the voters know it.
The idea that the country is lying in wait for a centrist was always untested.
Electability is inherently probabilistic.
Could a far-left candidate beat Trump? Sure!
Could a moderate candidate lose to Trump? Absolutely!
The question is which candidate maximizes the chances of victory. The evidence strongly points towards moderates.