The negotiating and comprising went across party lines. You are either misinformed or misrepresenting what has happened over the last 12 months.
A 5 second search on Google of "democrats negotiate with republicans health" came up with this Time article from mid last year questioning whether or not the Democrats would CONTINUE to negotiate with Republicans:
Can Democrats Reform Health Care Without Republicans? - TIME
Guess what, the health care plans haven't gotten any more leftist since then - actually the opposite.
Also form that quick google search I come up with a lot of links from Democrat bloggers from around September last year urging the Democrats to stop negotiating with the Republicans... so that is even after the Democrats had the numbers.
I'm sorry, but it is completely wrong to suggest that cross-party compromises and negotiations have not been occuring. The only reason they have stalled recently is because of a Republican refusal to move any more from their current position.