I remember 2008, and the path to 60 votes, and this was simply not true. Perhaps if Obama had started negotiating from single-payer, they maybe had would have gotten a public option. But a decade ago not enough democratic voters supported single-payer.
It is true. The Democrats had a filibuster-proof 60-member caucus[0] in the Senate, full control of the House, and the Presidency. They didn't need (and didn't get) a single Republican vote. But as they delayed while busy loading the bill with even more disastrous spending (e.g. community pools, Risk Corridors, etc.), their Senate supermajority fell to 59.
Caucuses are full of actual people who are worried about representing^W being reelected in vastly different districts. Party leadership can never rely on getting every vote; this is why whips were invented.
In the case above, there was zero bipartisan cooperation past the original proposal, so the individual senators really mattered.
So, they had to cooperate, that is compromise, take more viewpoints into account! That the end result is worse (as in, it costs a lot more GDP wise) doesn't matter, as it wasn't important for the participants anyway. Conservatives wanted to emphasise the personal responsibility (and sweet, sweet personal freedom to not plan ahead), they got it.
