"Sketch on the Mac costs $99, and we wouldn’t dare ask someone to pay $99 without having seen or tried it first," Omvlee said in a recent interview with The Verge. "So to be sold through the App Store, we would have to dramatically lower the price, and then, since we’re a niche app, we wouldn’t have the volume to make up for it."
Lot’s of great points that unfortunately have been repeated over and over in the last 5 years of iPad. If Apple’s intent is for this to replace desktop and laptop computers for many people, developers have to take the risk on the platform.
When the likes of Microsoft, Adobe, and even Apple are releasing software for free on iPad, the bar is set too low for prices. When developers cannot offer a free trial or paid upgrades, the only option is to price super low and make up for the cost in volume. But “pro” apps are typically a niche market. Developers cannot make a living from selling apps for $5.