As an iDevice user I am glad that I chose to buy all my devices with the absolute max storage available. Everything I have has 64GB. So, we are good for a little bit.
As a developer I cringe at the situation. I am currently working on an app that has about 400 graphics files that will ship with the app. If you do it their way you have to produce each one of these files in four different resolutions. This means that the image directory is now huge. It is three times larger than a scenario where we would have app bundles customized for each device.
In looking at the problem we decided to do the following. All of our files are produced at what would be @2X resolution but are named without the @2X. We are going to ship the app with just 400 files at a single resolution instead of 1600 files at four different resolutions. In the end, if you do the math, your app bundle will be significantly smaller due to the significant reduction in size of the images directory.
As far as performance is concerned, the images work very well all they way back to iPod touch v2.0 devices. No issues there. So, that's the plan.
Maybe what Apple is pushing all of us towards is a scenario where we are forced to detect device type and capabilities and load resources accordingly on app first run. Think about this for a moment. Now their servers don't have to push out so much content and you will have to foot the bill for your free graphics-intensive app getting three million downloads. I could be off base here. But, I just don't see a way to deal with this unless you are willing to ship your app with thousands of files, most of which will never be used by the device the app is installed on.
I also think it's high time that apple put out an iDevice with the ability to expand memory capacity in the field. I know, I know, they want to control it all. They are big enough to have custom Flash chips made with all the encryption they want so people can't move the flash chips from phone to phone and steal software.
Happy coding.