Airlines prefer business class customers (routine flights, willing to upgrade to expensive business class tickets) and those customers typically search for small 1-2 day windows.
We know airlines want this as much as consumers do, if it gives them a better ability to manage their capacity and market their products more efficiently.
We also hear it's a myth that airlines prefer business-class customers; on a dollars-per-square-metre basis they do better out of coach.
EDIT: Also note, most of the newest/fastest-growing/most profitable airlines in the world are low-cost and don't have business-class.
Presumably if Adioso are finding it worthwhile building their own price scraping/caching engine the GDS companies aren't willing to allow their systems to be [affordably] queried on that kind of scale. I'm just wondering whether they're claiming it's impossible for technical reasons, IP reasons (they sell price data back to the airlines) or just weren't willing to quote Adioso an affordable rate.