I think the most salient point in the article was the bit also mentioned by other recent opinion pieces, that Sanders should be doing more to actualize the 'revolution' by trying to help the Dems downballot. He has the attention of a large group of young engaged citizens who care about politics and are willing to send in donations. Obviously if he wins he needs help in Congress but even if he doesn't, shouldn't he be doing what he can to bring more like minded people into Congress to help him push his agenda. He has a great opportunity here.
I'm not really convinced that many of these people would give a damn about Congress even if Bernie asked them to. Many of them operate under "president is a dictator" mode and would likely sit out 2018 even if Bernie won. Due to our poor education system, there are tens of millions of Americans who think only the presidency is relevant enough to actually get up and vote.