Back in the 1980s you got your Mom to buy you a game console and you would have needed a logical naming scheme so she would know an PS 3 was better than a PS 2.
XBOX cultivates a "gamer" who is heavily invested in the identity and is well educated in the various versions of XBOX and how the naming scheme works and since they are an adult buying the console for themselves they don't need to explain it to outsiders.
sure i guess if you only want money from adults born in the 80s maybe it seems like an okay idea. abandon the market of humans born after the year 2000, should be fine.