No, we have less than 4 pagefuls of apps on our (admittedly 16GB) 1st-gen iPad, and space is pretty tight. No music and we only keep around about 1-3 hours of video at a time.
Games are by far the worst of course, but I'm sure part of that is down to the higher-res textures for iPad2/3 which are useless on the first iPad's much weaker GPU. (the difference is likely even worse between iPhone4S and iPhone 3GS or older) Adding a higher-res mip level for each texture in a game will increase the size of all textures by about 155%[1]. So in principle a 16GB/32GB non-retina iPad could store at least as many apps as a 32GB/64GB retina one, respectively. (not counting savings from losing all the iPhone/iPod touch assets, which will be big for non-OpenGL apps)
The iOS app update mechanism is also pretty broken when you're low on disk space: to update large apps, you have to delete the old version (deleting any of your data in said app) and reinstall with the new one, if both of them don't fit side-by-side on your device.
And as an app developer I'm already so used to jumping through ridiculous hoops to get apps onto the app store, so tagging files for different device types seems straightforward enough (and would help a LOT for reducing the size of one of the apps in the store that I developed - in fact, pushing it below the 3G threshold vs the current wifi-only size).
[1] http://wolfr.am/HUOxZ1
