I'm not certain it's over yet. Pelosi clearly doesn't want it to be over. She may be hoping the president will assert himself more forcefully and try to change the calculus in the House -- though he's shown no signs of being willing to do that. She may also be playing for time, hoping that her members in the House will get a deeper realization of the implications of abject failure (both in policy and political terms) and reconsider, that tempers (which are understandably running very high) will cool. Maybe some will reconsider; maybe she'll get more leverage to get a binding agreement from the senate about a deal to make changes in a separate bill.
What I don't believe is that this is simply a bargaining position, a posture to get the Senate or the White House to absorb some of the pain the House is being asked to swallow. I think what has happened is that the people in the House, collectively, don't have the mettle to make this happen. And we're in a very short window of time when they're able to take the action that kills reform while still believing that this isn't the inevitable result of their action.
I think it's still possible that there's going to be a second thought, a realization that there's nothing but Plan B. And I think it's possible that in concert with this, Dem Reps will be on the receiving end of a wave of dissatisfaction from Dems across the country. But I think it's only a small chance.
And the key reason is because it gets harder every day. And if they can't do it today, why does anyone imagine they'll be able to tomorrow.