Partisanship is not about policy
Adam Serwer explains why bipartisan legislation and centrist legislation are not the same thing:
The reality is that the "center" is not an ideological place but a political one, defined not by the nature of a specific policy but the political positioning of the right and left poles of debate. The reason why Democrats didn't produce a more liberal bill is because the coalition of preening centrists needed to move right every five minutes in order to locate themselves in the "middle" between a GOP sprinting to the right and a left willing to take major steps in the same direction. Moderate as policy, there was no way for the ACA to be "centrist" in the sense that the Village understands it, because Republicans were never, under any conditions, willing to consider voting for the bill.