I would suggest there are a number of reasons and not one key factor. The first three may be that: the communities most likely to help mitigate disasters in Pakistan learnt how to channel their funds directly to people they know during the earthquake relief operations, these highly effective methods bypass the DEC appeal and do not show up in the UN figures; secondly the media has tinged this appeal with misgivings which call into question the countries own response, mention the Taliban, talk about political problems etc which give donors a neat series of reasons not to give and was not the case in other appeals like Haiti and the Tzunami; thirdly the income comparisons are to the most highly effective appeals of recent years when the Pakistan DEC Appeal is already higher than the totals for the Indonesia, Philippines, Vietnam DEC Appeal, the Gaza Appeal and the Congo Appeal.
How much of a factor worries of the UK Government's savage cuts tripping the economy into a new more serious recession, which are already affecting the high street as shoppers fear they may soon lose their jobs, is hard to guage but it is also likely factor.
So, what should the agencies do? To a large extent the response is out of their hands as these large appeals are highly influenced by the amount and tone of media coverage, but building fundraising communities and driving them to reach milestones on the way to a clear target backed by the use a appropriate celebrities and using all fundraising channels including social media, txt, video etc is the base for todays successful strategies.