That's a little different, because there was guaranteed money for just creating an app. If Microsoft took a 0% cut, it wouldn't be that different for app spamme

That's a little different, because there was guaranteed money for just creating an app. If Microsoft took a 0% cut, it wouldn't be that different for app spammers - they'd still have to get people to pay for the app at some point. Ultimately I don't think the difference between 15%, 5%, or 0% is that meaningful to an app developer. It's not going to turn your small number of Windows customers into a huge number, and 95% of a small dollar amount is not much less than 100% of a small dollar amount.