Most people, myself included, predicted that if Sanders didn't win New York he would be pretty much out of the race. Admittedly, the math doesn't look good. Even if you disregard the highly debatable assumption that the superdelegates who have endorsed Clinton would defy the will of the voters in the event that Bernie pulled off a miracle, he will have to win a remarkably high percentage of Democratic votes in the remaining primaries to enter the convention with even a slim lead. There is a way that he could do that, however: Clinton-leaning Democratic voters in the remaining races could choose to vote for the candidate who best represents their views.
How many Clinton voters have you heard say "I love Sanders' positions on the issues, BUT"?" These reluctant "supporters" have been voting for her in large numbers only because they believe that she is the most viable candidate in the general election or that she is the one who could get the most done, regardless of all the evidence to the contrary. What if a significant proportion of them decided to stop rationalizing their decision to voting against their preferred candidate? While I am not aware of any poll data to back this up, I suspect this would give Sanders the edge he needs to bring in the kind of numbers that would make superdelegates think twice about defying the will of the voters.
None of the earlier arguments about why Sanders still has a chance have changed, even if the odds have dropped because of his unexpectedly sound defeat in New York. He still has the advantage of momentum. It's true that this has momentarily stalled, but one loss does not a trend make. He has still won seven out of the last eight races and is the favorite in the upcoming primaries. While Clinton's more fanatical supporters seem blind to the fact, superdelegates will surely have to recognize that the better Sanders is known, the better his poll numbers, while the more familiar voters become with Clinton's record (as opposed to her resume) the lower her favorability ratings. That's not what delegates endorsing her want to see when their own political futures depend on backing the winning horse.
In terms of electability come November, Sanders has won about as many swing states as Clinton, but may have a better chance in the general. He outperforms her with independents and continues to outpoll her in head to head polls against Trump and other potential Republican nominees. Add to this the fact that 25 percent of Sanders supporters say they will not vote for her, and there could be harm to the party's down ticket prospects as well since many young voters will likely not show up at all. Ignoring the anger at politics-as-usual, Clinton supporters have been demanding that Sanders supporters bend to the party will, hold their noses and vote for yet another corporatist candidate. Since they sincerely believe that it is only logical to vote for whatever politician has a D after his or her name, even those who say they won't vote for Sanders because they are upset at some of his supporters would be unlikely to withhold their votes for him should he be nominated.
Viability in the general election is by far the most important issue superdelegates should be concerned with, since that is what determines their reward for supporting a candidate. If enough Democrats decide that they are tired of voting for candidates who won't make a serious effort (if any) to fight on basic issues like single payer, a $15 minimum wage, ending destructive free trade policies, addressing global climate change, winding down endless wars or seriously taking on Wall Street, their reward will be even greater: They will have an advocate who will keep the spotlight onto the corruption of the political process that has led the party to the brink of selecting a candidate who epitomizes neoliberal and neoconservative values that are antithetical to traditional Democratic positions.