blackberry vs iphone apps

No, it's not another one of *those* threads. I see iphone apps working on 2g and 3g iphones - is that true of all apps? Cross version compatibility?
A big problem for RIM/blackberry seems to be that apps often need several variants to work on all bbs - is it really so hard to make 1 version for all bbs?
I think this is one of the key things Apple have right, and if we could get apps that worked on all bbs, we'd see fast expansion of apps.
Now I just need someone better qualified than I am in software to tell me it can't be done...

Posted from my CrackBerry at wapforums.crackberry.com

It's probably difficult to format an application for all blackberrys when there are so many different os versions floating around...bb's have been around a lot longer than the iphone, so the iphone software is probably much closer in proximity then the several bb versions

Posted from my CrackBerry at wapforums.crackberry.com

It's hard. We have 7 different screen sizes, so a lot of iPhone apps can have great UIs by doing pixel-precise code, or just using images for their backgrounds - But we'd need different code and backgrounds for each of the resolutions.

And then we have different functionality in each OS. For instance, you can only change the home screen image on newer OS versions. We can't rely on users to upgrade - It's a hassle for them to. Whereas the iPhone/iPod asks users to upgrade whenever they sync their music.

idk but i sure do want one of those handy dandy iphones.