Was it really all down to Obama and the endorsement game? Is there anything we can learn from it, or is the lesson "Dems will never accept even simple reforms and should be let go"? Most importantly: how do you answer when people say "you mean the same Bernie that couldn't even win the primary?" Other than the truth which is: Dems couldn't accept someone the party was completely hostile to, had the field been level we'd have sweeped.
It really should've been his to win.
The political system is the home turf of the capitalist class. Any ground gained there for the working class and against the capitalists is subject to a direct intervention in the system by capitalists (in the form of breaking the rules, violence, and then if the election is won, intentional sabatoge of production, flight of capital, brain-drain, etc.). I think a Bernie presidency was a pipe dream and the only real purpose the campaign served was to serve as a platform to radicalise people through.