First, thank you for that citation; it contains a great deal of information that I am still digesting.
Second, this claim of yours is not an honest representation of the results of those exit polls:
“Sanders’ major policy proposals are more in line with the Democratic electorate”
There’s only one question that addresses this. It is phrased as follows:
“A government plan for all instead of private insurance?”
And in fact, Mr. Biden is proposing just that. Here’s a direct quote from his website:
“Giving Americans a new choice, a public health insurance option like Medicare.”
His proposals do not go anywhere near as far as Mr. Sanders’; he proposes to continue building on the ACA to make sure that all Americans have affordable health insurance. But it’s clear that he is in fact proposing a government plan for all. It is not INSTEAD OF private insurance, as the question asked. Still, I think you are drawing a black-and-white distinction of a reality that is considerably greyer than you represent.
More important, that is the ONLY question addressing the policy proposal differences between Mr. Biden and Mr. Sanders. There is absolutely nothing about Mr. Sanders’ most ambitious proposal regarding the Green New Deal. There is absolutely nothing about his proposals to tax wealthy Americans. There is absolutely nothing about his proposals to install workers on corporate boards.
Thus, the exit polls do not show that “Sanders’ major policy proposals are more in line with the Democratic electorate”.
You are making a mountain out of a molehill.