I'm not sure I agree that the 8K is made redundant by this announcement. There's no mention of screen res. Without increasing the res, the SDE will be worse than the Rift. There's a big difference between 140 and 200 degrees.
Where did you see a price? With the complicated varifocal mechanism, I think it would be hard for Oculus to hit $800. Plus this is a tech demo; how soon would actual headsets be available?
It is good news for VR as a whole, to have more wide FOV headsets out there.