They may well be able to do all the things a low end laptop can do, as observed by the netbooks running Windows XP, but that doesn't mean that that's how they should be marketed. The 10" models and the WinXP models are blurring things a bit though.
I maintain that they should be set up and sold as a cheap machine mainly for Internet type tasks (email, web, chat, etc), somewhere between a smartphone/PDA and a low end 'proper' laptop. A customised Linux OS would be perfect for that and when marketed in that way people wouldn't expect Windows and could be happy with a Linux OS.
I don't know how big the market is for something like that but if someone buys one expecting to run Office or other Windows software they may be better off with a cheap 'proper' laptop anyway. I can't even imagine how usable an office suite is on the 10" 1024x600 screen on the latest Eee PC.