The original EEE 700-series first came with Linux distro, Xandros. However, soon the company learned that the majority of the people want to run Windows OS on their netbooks. Currently, almost all the netbooks run Windows XP as their OS.
Personally, it is due to fact that people have developed a perception that Linux is only for hardcore geeks which is not true at all. However, we have to admit that the App Store (package manager) in Linux needs to be more friendly. Users often get confused when they are required to execute scripts, grant access etc.