Nick is pointing to a key market failure in development. Donors are effectively buying their own services -- either literally or because of the revolving door with international consulting firms.
I strongly agree that it's critical to improve the information client governments have about different options and create mechanisms (like decision support) to facilitate action. Another complementary approach would be to weaken the ties between donors and providers of advice by increasing the capacity of in-country or regional experts whose strongest links are to governments. This also could also make governments better able to act on information about different approaches. (Of course it introduces other governance problems but there should at least be a healthy tension).
At Partners In Health we have just launched a project with Rwanda's Health Ministry along these lines called the "Non-Communicable Disease Synergies Initiative," which will create a horizontal technical collaboration unit within the ministry with support by key national institutions of higher learning. Two bilateral collaborations (with Liberia and Ethiopia) have been agreed on this year, with four more to come in 2014. If it proves viable, this model could be another way to make the market for development advice more responsive to countries' real needs. The first network meeting will be July 15-16 in Kigali.