Yeah I agree it seems like such a waste. It's probably done to inflate battery life numbers but it makes me even more leery of notebook manufacturers. I've had my current netbook for about 5 years now and it's been fantastic but it's definitely starting to show its age (even after adding a dual core processor, SSD, and bringing the memory up to 4GB). At the moment, it's really only used for web browsing and some office use. Anything else, like light gaming or hulu/netflix/youtube really starts to bring it down and I'd really like to be able to do those things.
I just wish it were as easy as building your own PC -- as odd as that is to say. All the specs are there. You just get what you buy. Ideally, I'd love a 11.6"-13.3" laptop with Trinity/Richland and a user replaceable battery, hard drive, WLAN card and memory at around $500. I'd be willing to swap for a dual core kabini as well. I don't think I'm asking all that much.