Why is it called the Xbox one?
Because it's a prequel to the Xbox and Xbox 360.

I'm surprised they didn't learn from Apples mistake:
Ipad -> Ipad 2 -> New Ipad -> Ipad Air -> Ipad Air 2 ??
Don't forget about the iPhone.
iPhone
iPhone 3G (new 3G device, so this is ok I guess)
iPhone 3Gs (s represents a modified version of the previous phone, ok so far)
iPhone 4 (technically the 4th phone, but it's worth mentioning that this phone was NOT 4G)
iPhone 4s (modified version of the 4, so the s makes sense, by the way, this one WAS 4G)
iPhone 5 (WHAT??? This was not the 5th phone. Now I'm angry)
iPhone 5s (modified version of the 5 which was really the 6th iphone)
iPhone 5c (cheap ass plastic phone)
iPhone 6 (because fuck the consumer)
AVGN should do another chronologically confused.