Apple could let Adobe give it a try to bring Flash to iPhone/iPad, but it won't work anyway. And for end users it's better to prevent such a ridiculous effort completely.
iPhones have 128 MB RAM, 3GS and iPad have 256 MB. Most of it is used by OS X and the cocoa touch framework. For applications of the 128 MB there's about 30 MB left I read somewhere. And with 256 MB we don't want to waste memory either: Multitasking (some sort of) is coming - and it's obvious why it doesn't work on 128 MB iPhones and iPads: there's just not enough memory to keep multiple apps or even just parts of it loaded.
I even wonder how Apple managed to implement a working browser - Safari - using only that amount of memory. So no room left to add a Plugin (e.g. Flash) to the browser.
Vice versa? Let's create a stand alone flash application using the CS5 Packager for iPhone. See
flash-on-the-iphone. Implementing flash means to duplicate many things that's already implemented in OS X and cocoa touch. And that computes to eating up memory.
My computer has 8 GB of RAM and I'm a java developer. So I don't have to care about 20 MB libraries, some MB of native JVM code, a hotspot compiler that compiles my code into native code (again sucking memory).
A "hello" wold program in C/C++/Objective C is some KB, using any other framework it blows up to use MBs.
Programmers have become lazy. My first computer had 8 KB of RAM and I learned how to spare it.