People who read too much into straw polls should remember all the times Ron Paul won them while not becoming the Republican nominee.
Bernie is going to get the Ron Paul treatment. The money he's raising and the amounts that he's raising it in will be minimized. The media will talk about him as little as possible. When they do talk about him, they'll talk about "his fringe status" and how he's only here to ask the tough questions to the real (establishment) candidates. He'll be marginalized at the debates, with the least amount of time possible, while being asked questions that are designed to make him sound unelectable.
Heads of DNC state committees, who've already got a mouthful of Clinton shoe polish, will completely disenfranchise Sanders. They'll block delegates and retroactively change rules to get the desired result. They'll probably institute a few new rules to make sure an upstart like Sanders never gets his foot in the door again.
Out of the ashes of the Sanders campaign, you'll see the "rise" of a pseudo-populist, left version of FreedomWorks...headed up by someone like David Axelrod.