Because a Democrat is in the White House?
Because health care costs have skyrocketed?
Because free marketed ideologies have been discredited by the financial crisis?
Because Obama is especially charming?
The principal reason these debates are happening now is none of these things. The sea change in public opinion on health care over the past few decades is a result of the international predominance of capitalism and democracy.
During the Cold War, for instance, Americans were much more sensitive about socialist reforms. Now, a minority of Americans expresses such concerns.
At the same time, the idea of taking a huge economic risk in the midst of a focus on international political competition with, say, the Soviet Union or Islamic fundamentalists, was extremely frightening.
Finally, of course, the focus on human development has grown with the increase in the value of human capital in the global economy.
So, the global triumph of capitalism and democracy has (1) reduced ideological sensitivity, (2) shifted our focus away from international political competition, and (3) created the conditions for international economic competition, based on human capital investment, to take on increasing importance.