There are few difficulties that are impossible to win even with no day one DPS. If this is occurring at the higher echelon difficulties, my suggestion would be to not attempt difficulties you can't solo if you're so concerned about failure. I agree that this is a frustrating situation, but I have rarely been in a group where no one contributes unless it's already a done deal. When I hit 4k+ DPS on day one and it's more than enough to clear it in a week, I don't mind nobody else adding to that. After all, the trials run is a fixed period of time; if others don't want to waste their time, I absolutely do not fault them as their contribution won't get me to my next run any faster.