I honestly don't trust them to make the right decision given the fact that they've done everything to clinch it for her. The way business and politics are intertwined they would feel like they are risking their pockets and/or political career. I think intense public pressure within states he's won may be something that could change em. Any possible news (indictment, David Brock shenanigans and other fukkery) could change votes as well (supers and actual voters). There's a lot of time before the convention.
I think the longer it goes the worse of a candidate she looks as favorability keeps going lower and bernies numbers go up. He has the case of independents siding with him and the south going red in the general. Having the youth and independents help expand the party. Her claiming to have the support of older voters as a strong point is weak because you are essentially saying the people that would vote dem anyway vote for her while the youth won't (but would at least more for Sanders) and independents will somehow get to liking her more eventually given the alternative. This we'll get them later attitude pisses ppl off. You are putting independents up for grabs. He needs to win Calfornia for sure. I think he needs to get within 50-75 delegates and possibly the popular vote.
In my mind, I see them choosing her than something popping up that makes them regret it. Faced with a lesser of two evils as dirt gets exposed on both perhaps he comes as a third candidate or in a bizarro world she's forced to step down and Bernie takes over. I'm still hoping people wake up.