A commenter from Arstechnica had a good point as to why the wallpapers weren't enabled on the iPhone 3G.:
Hey, just wanted to make a quick comment on this:
"Additionally, this feature appears to be disabled for iPhone 3G and second-generation iPod touch users. Why? Nobody knows. Apparently you really need some hardcore processing power in order to display custom wallpapers."
I know why, and I'll tell you exactly why.
In implementing homescreen wallpapers, Apple realised that (as is clear from many Jailbreak themes) custom backgrounds often look rubbish and/or reduce usability. To counteract this they've added drop shadows to all the icons and text which make it much more readable / attractive. Unfortunately this runs like crap on a 3G (and you can test this on a jailbroken device, google "enable homescreen wallpapers 3g"). So Apple were left with 3 choices:
1. Enable it on the 3G, leaving it running like crap.
2. Enable it on the 3G, but remove the shadows making it look crap.
3. Disable it on the 3G completely.
Apple being Apple they'd rather have no feature at all than implement a feature at even 95% of the quality it could be.
You may or may not disagree with that decision of course, but that is definitely why it isn't available on older devices.
Hey, just wanted to make a quick comment on this:
"Additionally, this feature appears to be disabled for iPhone 3G and second-generation iPod touch users. Why? Nobody knows. Apparently you really need some hardcore processing power in order to display custom wallpapers."
I know why, and I'll tell you exactly why.
In implementing homescreen wallpapers, Apple realised that (as is clear from many Jailbreak themes) custom backgrounds often look rubbish and/or reduce usability. To counteract this they've added drop shadows to all the icons and text which make it much more readable / attractive. Unfortunately this runs like crap on a 3G (and you can test this on a jailbroken device, google "enable homescreen wallpapers 3g"). So Apple were left with 3 choices:
1. Enable it on the 3G, leaving it running like crap.
2. Enable it on the 3G, but remove the shadows making it look crap.
3. Disable it on the 3G completely.
Apple being Apple they'd rather have no feature at all than implement a feature at even 95% of the quality it could be.
You may or may not disagree with that decision of course, but that is definitely why it isn't available on older devices.