It has everything to do with people naysaying. Bernie Sanders absolutely can win both the primary and general elections and he can spearhead radical change in this country as president... if the people who agree with him actively support him every step of the way. His opinions are those of most Americans. If everyone who's saying "I like him but he has no chance" were to instead actively support his campaign (donate $5 every month (because he's not a corporate whore), talk to their friends and relatives about him (because many people either don't know who he is or have mistaken ideas about him), attend a local meeting or rally (which is the best way to compel the media to cover him), vocally criticize those who dismiss him as irrelevant (because they're wrong)) he'd win. My 61-year-old mother went from a lifelong registered Republican to last week asking me how to re-register as a Democrat so that she can vote for Sanders in the primary. She's about as basic as a Judge Judy/Two and a Half Men/American Idol watching, Bejeweled playing baby boomer gets, yet here we are.
I'm not resigned to living in an oligarchy. If you are, that sucks, but stop trying to impede those of us who are willing to fight against it.