Apple gives developers access to hundreds of millions of customers that have proven they’re willing to pay for digital content. The developer has to bring their skills/ideas, the price of a Mac, and $99. Beyond that, if the developer doesn’t make a sale, Apple also doesn’t make money. If the developer does end up actually creating something desirable (which depends on their skills/ideas/code abilities of course) and makes, say $20,000 in one month, they get $17,000. Offsetting $3,000 in order to have $17,000? I don’t know too many people that would turn down that cut.
Now, here’s the real question. Are they actually able to take advantage of the opportunity and eventually make a living wage or much, much more? The truth, for very many developers (the vast majority of developers, in fact), is no. You could direct hundreds/thousands of dollars in their direction (there’s no way to make it any easier) and they just wouldn’t be able to profit from it.
They’re most certainly free to keep trying as long as they like, but, and some may find this part hard to believe… everyone doesn’t become a star in athletic pursuits, everyone’s not an intellectual powerhouse, and not everyone has what it takes to be a developer with the abilities to make a profit when given access to hundreds of millions of people who, again, have spent considerable sums previously. If their idea of being a developer is “guaranteed payday made easy for me”, reality would like to sit them down and have a heart to heart.