There are several reasons for the GOP to do this. What is worth noting is that this has happened, for the first time, without much drama. In fact, we had a sudden exit of drama queens after seeing a veritable drama queen convention since November. So naturally the question is, why?
A few thoughts. It should be noted this does not mean that GOP House members have suddenly changed their overal opinions or are suddenly more willing to engage. But the current dynamic is interesting.
1. Obama won reelection. Much of the strategy of the last four years was based on a calculation that Obama could be defeated by denying him significant wins and pining him with the blame. For whatever reason, that did not work. But it is now irrelevant. Even if Republicans have no interest in policy and are looking solely at how to take the White House in 2016, it does not appear that a pure obstruction strategy is going to be helpful.
There is also the fact that a number of Republicans actually do have stuff they, or their constituents, want done. Grinding everything to a halt for another four years is a very long time -- and may backfire in 2014.
2. Republicans have seen significant slide in brand In 2010, the electorate blamed the President for its unhappiness. In 2011, the electorate (based on polling) was apportioning blame pretty evenly between Republicans and the President. By the end of 2012, generic blame for dysfunction in Washington was being increasingly apportioned to the GOP. That is not a terribly good place to be.
3. House leaders showed willingness to move without Tea Party Wing. Part of the driving dynamic until now has been that the Tea Party wing has been unwilling to compromise in any way, and the leadership have been unwilling to move without a majority of the GOP. In two major votes, however, the leadership opted to pass bills with Democrats despite a majority of of GOP members voting nay.
In the short term, this intensifies the divide. But it also makes a truce between the leadership and the Tea Party attractive to both. Neither side likes being at war with the other, and a short term break to take the pressure off allows time for both factions to work things out.
4. GOP desperately needs to change narrative. Linking the debt ceiling to forcing the Democratic Senate to come up with a budget that will pass the Republican House allows House Rs to change the narrative. Right now, the "Congress already bought this stuff, now doesn't want to pay the bills" is resonating. In the next three months, either Congress has a new budget or Rs can blame the Senate for its failure to do its job.
So I don't see this as particularly indicative of how things are likely to go once we get down to May. On the other hand, even a few months of relief from the Drama Queen convention would be a welcome relief.