In short, at first you think the problem is easy because you don't understand it. Then you begin to understand the problem and everything becomes terribly complicated. Most people stop there, and Apple used to make fun of the ones that do.
To me this is the perfect visual illustration of the crescendo of special cases that is Swift.
The answer to this, according to Steve, is "[..] a few people keep burning the midnight oil and finally understand the underlying principles of the problem and come up with an elegantly simple solution for it. But very few people go the distance to get there."
Apple used to be very much about going that distance, and I don't think Swift lives up to that standard. That doesn't mean it's all bad or that it's completely irredeemable, there are good elements. But they stopped at sophisticated complexity. And "well, it's not all bad" is not exactly what Apple stands for or what we as Apple customers expect and, quite frankly, deserve. And had there been a Steve in Dev Tools, he would have said: do it again, this is not good enough.
As always, comments welcome here or on HN