Netbooks were a REALLY cheap limited function/small screen laptop.
They never competed well with laptops and were designed to surf the NET. They were successful because they were cheap. But the experience was far from great.
The iPad did easily beat that because of ease of use and even better functionality with touch, since the netbooks small screen made using castrated Vista/Win 7 kinda awful. Now that netbooks are gone the Ipad momentum is slipping.
Tablets are content consumption devices that are very mobile-handheld, they are poor content creation devices. P.C.'s are great content creation and consumption devices. Do you really believe that most of the content on tablets was created on tablets?