In my case, that turns out not to be the case. I work very quickly.
I can develop a fairly "full-fat" iOS app, with a lot of functionality, in less than a week. I do it all the time, with test harnesses.
But getting the app to what I consider "ship" shape, is another matter entirely, and can stretch the project to a couple of months (which is still not so bad, all things considered).
One of the nice things about my approach, is that I can start using TestFlight (Apple's beta-test service for iOS) quite quickly. This allows non-tech stakeholders to start actually using the app, very early in the process.
If I have an open-ended schedule (like I do, with the project I'm working on now), it's amazing, because we can refine the project, and work through a lot of the MVP stuff, without the public shame.