A long read but worth it.
Some Key Points
-XB1S and Scorpio planning started almost immediately after the XB1 launch.
-Scorpio actually had two different prototypes like Neo did. A 2016 version and 2017 version.
-Scorpio in its current form was based on a price point that a console gamer would want to pay.
-A main reason for Scorpio being tied to XB1 is because single games are starting to span generations.
-Main reason for Scorpio was that XB predicted 4k growing faster than estimated and wanted to cater to that.
-XB has constantly been making handheld designs/prototypes and streaming USB sticks, but hasn't ever pulled the trigger.
-VR is still early, and XB is still working on it and has plans, but for now will simply support other VR devices and games on Scorpio.