I'm not saying one should download/stream everything. I'm saying that it's not that difficult to keep your most commonly listened to music on your device. 64 GB holds plenty for me. It's pretty rare for me to need to download a song.
As for videos, for non-iTunes purchased video I keep it on a server at home from which I stream with Plex. Usually on my iPad. If I'm on the road, I plan ahead of time for what I want to bring. If I know I won't have WiFi or 3G (again, rare), I download just what I plan on watching. Video consumption on my iPhone is a non-issue because I just don't enjoy watching movies or TV shows on that small a screen.
And I think this will be even less of an issue once LTE gets widespread rollout. I get that people have different usage patterns. But I have trouble believing that anyone fully utilizes their entire media library during periods of no high speed connection. And if you do, I'd argue that you are a minuscule proportion of the population.
BTW, what apps are you using that take 2GB? I'm just curious because I'm looking at my phone apps and the largest one I have is Weather HD at 327 MB. I'm not counting Music which is at 3.5 GB because of course that includes a lot of songs.