You're paying for compute, whereas you can put an app on a store for (basically) free. A million people can download your app and you wouldn't pay a penny more, whereas if a million people suddenly used your AWS app, you'd see a nice bump in cost.
as per my previous comment, they could charge a fixed price per view/download and any other functionality of the app store. It would be the same price for everyone, regardless of revenue, and for most apps, it would be less, fairer, and more transparent
It could be an option, but there is also value for everyone, poor or rich, no matter in what country, being able to host an app, no matter no popular, without going bankrupt. It's the same with Youtube; the ad-model is not ideal, but there is also value to being able to, with the click of a button, host a video that can be watched by millions of people without you paying a penny. Two decades ago that would've been very hard for an average person to do.
