It's entirely possible that Ed Kilgore is right:
Progressives are waiting for Barack Obama and his team to work the kind of political magic they seemed to work in 2008--except when they didn't. Cutting through all the mythologizing of the Obama campaign, the real keys to his stretch-run success last year were his legendary calm ("No Drama Obama"); his confidence in his own long-range strategy; his ability to choose competent lieutenants and delegate to them abundantly; and his grasp of the fundamentals of public opinion and persuasion. There was zero sense of panic in the Obama campaign itself late last summer, because they stuck with their strategy and organization and didn't let the polls or news cycles force them off the path they had chosen.
The administration's demure approach should thus not be terribly surprising, nor a sign that it has lost its heart or its mind. Obama has not, presumably, lost the qualities he showed in the tougher moments of the 2008 campaign. As it planned its legislative agenda for 2009, Team Obama knew health care reform was going to be challenging, and also knew they could probably get away with blaming the economic emergency for paring it back or slowing it down. They decided this was the right time to act, and it's far too soon to assume they were wrong.