I'm not sure that is strictly true. The autoresize model[1] will cover a lot of cases. The place where it does break down, and where HTML does shine, is with variable sized data such as paragraphs of text. However, that is starting to encroach on document territory anyway – meaning you'll probably want to use something like UIWebView to display that data.
Anyway, not trying to point out the obvious. I've just noticed that not all iOS devs are even aware of the autoresize functionality, so I figured it was worth noting.
[1] http://developer.apple.com/library/mac/#documentation/Cocoa/...