I didn't have a problem with my Acer netbook. It's slow, but not horribly slow. The main laggard factor is the 1gb RAM, which is too little for a Windows 7 install.
However, I had to remove all the crapware first. If they didn't ship with those installed, they wouldn't make money from all those juicy contracts.
Someone further down mentioned a beer-induced $800 repair on a MBA. I dropped half of mine in a sink of water (don't ask) and it works perfectly. Tested the 'splash proof' keyboard quite thoroughly.
Definitely a market for lower-end sub-$500 machines that are actually capable of running anything.
In the sense of a true netbook-as-a-thin-client, the Chromebook is the only competitor in this market. What you have with 6GB of RAM and a large hard drive is a small form factor laptop. I agree that there's a market for lower-end cheap laptops. I disagree with calling them netbooks, because then you get confused posts with people asking what the point of a netbook is. The Chromebook is the point of a netbook.
Some Sun partners tried. https://en.wikipedia.org/wiki/Sun_Ray
and
Cue a few years of Moore's Law, and the net effect of a market for affordable yet usable portable machines produces capable, upgradeable machines. And tablets. Cue content producer/consumer distinction etc.