Well duh. DCA is in a large city. IAD is out in the country. And everyone out here does use IAD. It doesn't make any sense to drive in to DCA if you live near IAD. But you said there is nothing easy about flying out of IAD. That's not at all true. I use both airports and there is nothing about IAD that makes it harder than DCA, assuming you are arriving by car. And on the inside IAD is much more pleasant in most areas, especially terminal B which is new with lots of space. DCA has small crowded corridors. That said, I will always use DCA if I happen to be in the District and flying domestically.