This sort of has been solved for 50 (wild guess) years with portable music players. Sure it is not exactly the same, and sure there's the extra recording step,

This sort of has been solved for 50 (wild guess) years with portable music players. Sure it is not exactly the same, and sure there's the extra recording step, but once that is done (which for downloadable stuff nowadays takes a fraction of the playback time) you have something which is better in some ways because it's offline. Don't get me wrong here: I'm not acvocating to go back, but in some ways it's strange to see new technology being used so widely yet people suffering to get things done which were actually better with older technology. Battery life is another one. The 2 of them combined in an example: I have a rather old portable player which takes micro SD cards. Even without swapping that's a huge amount of music. 2 AA batteries and the thing lasts for hundreds of hours. So purely for playing audio that solution really owns anything newer. Then again, it's of course also the only thing it does.