Xbox - It's named after DirectX because they wanted to bring games to the living Room
Xbox 360 - It's named after you being at the center of the Xbox ecosystem. They also named it Xbox 360 instead of Xbox 2 because the PlayStation 3 was already announced and 3 is a higher number then 2. Remember, average people don't know the overall difference between these systems so most are probably think PlayStation 3 was a newer system.
Xbox One - That's pretty much just named because it's an all-in-one box. You can play games, watch movies and watch live action TV basically no reason to have a set top box anymore.
Xbox Series X - With this I think they're just giving up naming systems down the road now. Kind of like everything else in the world, You got an iPhone 12, Iphone 12 Mini and iPhone 12 pro. That's why when you launch the Xbox series X/S It just says Xbox.
Now granted I did do that where I called the Xbox One X the Xbox series X and the Xbox series X Xbox One X but I also did that with the PlayStation 5 with the PlayStation 4 only because it's the newer system is meshing with the older system. It's been 2 months since they been out and I have not made that mistake.
You know what really is a lazy one though is PlayStation. I mean we already know what the next one's going to be called
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