Both can be true. I've done mostly web, but I now work for a company that ships both iOS and Android apps and the cost of dealing with both Apple and Google app store compliance/review is not negligible.

At the same time, I'm sure they're both getting blasted with knockoff apps that find ways to stay just within the letter of the law, if not the spirit of it.

> I wonder if I made an app that was simply a front-end for the actual app store if it would be approved.

It would not, as the primary purpose of this entire enterprise is to maintain total control of all aspects of the market, including discoverability.