It's an argument I'm finding harder all the time to disagree with. I love indoor track. The intensity of it, in a smaller arena with the fans at the very least feeling much closer to the action, is amazing. From both a fan's viewpoint and an athlete's viewpoint, I've always found it to be a much more high energy atmosphere than outdoor track.
That said, the big fish is outdoors. With limited resources that appear to not be able to be adequately spread over indoors and outdoors, we should focus those resources where it counts most. That would be outdoors. I hate to say drop the support for indoors because it's something that I have such a great appreciation for but it would be a huge disservice to the sport to keep indoors on life support while outdoors wilts. Prop up outdoor track in support of the Olympic Trials and Olympics (or US Champs and World Champs/Diamond League/etc in other years) and, if you must, let indoors sink or swim on its own.