Bernie would not have been close to losing. Appointing another typical Democrat to represent the party will only result in close elections that can swing either way. Trump took that small margin of a win because he was not your typical candidate.
If either party can choose someone who will stand against the oligarchic trend, then there will be no contest against them. Such a candidate in either of the controlling parties would allow voters to rise above their fear based decisions as well as energize disenfranchised voters.
So yes, I am suggesting she was unelectable for those reasons. A coin flip win is clearly not electability.
I just realized a good analogy. Our two parties are comparable to Nascar in that they are stock cars with little to no room for modification that would make them faster vehicles. Trump won because was giving the middle finger to the other drivers. Bernie was disqualified because he was cheating with rocket boosters on his car.
It got Bush elected. It got Trump elected. It got Biden elected. If you think 50/50 means electable, then you really don’t care who wins.