Netbooks were actually great. I loved mine. It had 11 hours of battery life (this was around 2007 or 2008 when typical pc laptops were getting 2-4 hours). A lot of my classmates liked their netbooks too. The ultrabook is also fantastic, but much more expensive (I'm typing this on a $2000 ultrabook, my netbook was $200).

There were many popular netbooks before the MBA came out. Apple showed that there could be a popular high-end version with excellent build quality and now the market is responding with a cheaper model with the similar build quality. This isn't stealing. It is the standard model of almost every popular consumer electronic device since the 1980's.