There are thousands of new apps on the market on a daily basis, all of them overlapping with each other and apps that are already on the market to a greater or lesser degree. Who is going to reduce that flood to the "best" of a particular category, worthy of your time and money, and on a regular and timely basis?
Granted, current app stores could be better, but you'd still have the discoverability problem simply due to the volume of apps now on the market.
