Clearly, the single most vexing shortcoming of the iPhone is its lack of text selection and clipboard features.

But, I not only understand why they’re absent today, I can even see the argument that — while they’re essential — it’s good that the 1.0 iPhone shipped without them. And therefore, alas, why it might be a while before they appear.

Whatever Apple comes up with, it doesn’t have to be spectacularly clever. It could even be an off-by-default preference, like the caps lock feature, so as not to clutter up the screen for typical users. The 80/20 rule says you spend 80 percent of your time using 20 percent of the features. The genius of the iPhone design is that they’ve already covered the common side of the 80/20 rule. But without text selection and a clipboard, the uncommon side remains out of bounds.

https://daringfireball.net/2007/08/clipboard_and_arrows