Well, they can always take their business elsewhere, where the grass is greener. But they came to the App Store because it's a dozens of billions of dollars a year market...
This sounds almost like the developers should be permanent, pardon my French, bitches to both Apple who can boot them for any petty reason, and to scammers who copycat them and make money with straightaway fraud, then to Apple again, who won't do anything about the scammers (I wonder what percentage of App Store revenue comes from those, once you look past the biggest players like Microsoft/Adobe/whoever else is in the top 20), and then to Apple again, who will incorporate your app's functionality into the core of their OS offering and then boast how they were the first to come up with the idea.
And not only should be the developers bitches, they should, according to you, accept and enjoy this dubious "honor".
You can build an app that only serves an extremely narrow market niche to improve functionality that is incredibly important to the platform owner, but then you shouldn’t complain about being sherlocked or how tough competition is.