Earlier quoted context omitted.
Acer/Lenovo/Dell can't risk getting sued by Apple. Xiaomi is a Chinese company they don't care since if they ever do get sued the Chinese court will always side with the Chinese company. The again if the clone works just as well as the original I don't really care but this would have been a really good chance to copy and improve.
Well, if we're talking copies, then Airs are just a scaled-up version of the eeepc - same 'sharp wedge' shape (that is apparently why Lenovo X1s are being called clones of Airs). The eeepc was the thing that proved there was enough interest for a low-power-but-mobile computer, which ended up turning into the tablet market. Crappy build quality, but people went berserk for them.
Really? Here's one [0] from approximately when the Air came out and looks not even remotely similar to me in shape.
[0] https://commons.m.wikimedia.org/wiki/File:ASUS_Eee_PC_PIC_09...