His quote does seem a bit high. In my experience (Rails and iOS developer) if your back end is mostly RESTful resources and a simple data structure, and your front end is standard iOS components like simple tableviews and a NavigationController, you can get an MVP done in the $5k-$10k range in a week or two.

HOWEVER: everybody has a different opinion of what is meant by "Minimum", "Viable", and "Product". $5k gets you only bog-standard UI components and a simple data model. Animations? Fancy graphics? Optimized performance? Search? Custom UI? Graceful error handling? Localization/Internationalization/Translation? Integrating with Facebook and dealing with their constant poorly-documented changes to their API? These tend to be little bullet points in the spec, but each on their own can take as much work as the MVP does.

With modern tools it's pretty easy to build a basic version of an app quite quickly. But it turns out that most people don't actually want a basic version. Often they have to see the basic version first to realize that, though.

So the question ends up being: how important is schedule/cost to you compared with details/performance?

To be honest, though, most people who come to me wanting a simple iOS app are better off with a mobile-optimized webapp instead. Much quicker to build, already cross-platform, and no deployment delays while waiting for App Store approval. Mobile apps might not be as sexy as a native app, but saving lots of money is also pretty sexy.