I disagree. Sanders was a genuine chance, if given equal billing and support. No one likes Clinton. She will be the biggest 'default' president in history. On the upside, Sanders forced her more left, and if she sticks to her campaign promises, it's a good thing. Unfortunately, I'm not betting on that 'if'.
And I could win the Nobel prize for Science if they'd only accept my submissions.
C'mon, be serious. Nobody is going to give a complete unknown the full support of one of the largest (certainly richest) political parties in the world just because he generates well with socially conscious youths. Especially when he's going up against someone who has already spent 8 years in the White house and since forged a credible political career of her own as a senator AND Secretary of State. It would be like Peter Garrett quitting Midnight Oil before their peak to become an MP who then deposes Bob Hawke.
Sanders couldn't secure the Black vote. He was battling against the fact that he's another old white bloke when it comes to the female vote. He could never hope to raise enough financial backing to go up against Trump. Hell, the networks could have been a wall to wall Bernie gang-bang on their shows but it's a moot point if Clinton can own every ad-break.
The primaries are in the hands of the party members. People who are politically active enough to pay membership dues, regularly vote and therefore -you would assume- are a lot more likely than joe public to look into all the options available to them when choosing their candidate. Sanders couldn't win over enough of them and it would be difficult to see him do any better with the general populace.