It's a question of the trade-offs to achieve that week of battery life. I have an extended battery for my phone which makes the phone bulky, but the battery lasts for nearly two days on a charge. If I were to significantly underclock the CPU and GPU, turn down the screen brightness, disable apps from running in the background, turn off GPS, keep data off, get an even bigger battery, etc., I could probably get a week of battery out of it, if not more. That would take away a lot from the experience though, and since I'm almost always near a power source, I'd rather keep the above features and charge every day. If you weren't, you might think that those tradeoffs were fair.

That's an interesting point that the parent post made - we probably shouldn't be thinking about these devices as just underclocked versions of first world devices. I think that you could design a positive user experience with all of the restrictions that I listed above (not ideal, but still positive), but it's not going to be achieved by disabling features of a super phone/tablet.