It wouldn't surprise me if most of the folks making $100K+ on their apps are spending double or triple that for development across multiple apps to produce a hi

It wouldn't surprise me if most of the folks making $100K+ on their apps are spending double or triple that for development across multiple apps to produce a hit. This isn't all that different from other hit-driven industries like music or video games. The exception may be in apps that serve a profitable niche and have little to no competition. But the problem there is it's difficult to stay on top when the marketplace is becoming crowded with fast followers. There are ways to defend against this, but it will involve building a brand outside of the App Store, which can take considerable investment.