A development simplification approach like this has been repeatedly tested on different platforms.
You always have a problem that in the development infrastructure there will not be any functions that the "real" system has, and although the transit mechanism is sometimes proposed, it is always clumsy.
Sometimes they offer speed gains, but the extent to which they benefit you depends on which domain you are in. Unity is a great example of a structure that obviously saves people a ton of game development time.
I personally think that outside the games I do not think that the advantage of using a third-party structure is really worth it. All the best applications are those that use the system to the full in terms of animation or user interface capabilities, which means that someone, having spent some time developing, will be able to make a more attractive application than someone who should rely on frame abilities.
Another problem you may encounter is that no matter how popular the third-party structure, you will always have more support for the official platform - for example, the number of books around the world today according to the version of Objective-C and iPhone, or even very active support for Objective-C on this very site.
The only exception would be if you had a cross-platform application and application-supported development for all the platforms you need. But even then I will argue about how to make the iPhone application great and make full use of the platform, or your application will languish, and other competitors will defeat you.