A letter from Steve Jobs about why they don't allow Flash on iPhones, iPods, and iPads. (Notice he specifically uses the harsher "allow" instead of the much softer "support".)
Though the operating system for the iPhone, iPod and iPad is proprietary, we strongly believe that all standards pertaining to the web should be open. Rather than use Flash, Apple has adopted HTML5, CSS and JavaScript -- all open standards. Apple's mobile devices all ship with high performance, low power implementations of these open standards. HTML5, the new web standard that has been adopted by Apple, Google and many others, lets web developers create advanced graphics, typography, animations and transitions without relying on third party browser plug-ins (like Flash). HTML5 is completely open and controlled by a standards committee, of which Apple is a member.
Jobs sort of circles around the main issue which is, from my own perspective as heavy web user and web developer: though Flash may have been necessary in the past to provide functionality in the browser that wasn't possible using JS, HTML, and CSS, that is no longer the case. Those open web technologies have matured (or will in the near future) and can do most or even all of what is possible with Flash. For 95% of all cases, Flash is, or will soon be, obsolete because there is a better way to do it that's more accessible, more open, and more "web-like".
