The same should be true of a 970 with Oculus Rift. Over time it will obviously fall behind in being able to max out game settings, but it should at least be capable of native res at 90fps at some setting combination for a long time.
Part of the recommended specs from Oculus was a commitment to stick to them for the life cycle of the HMD, so I'm figuring that means we get a good ~2 years of the 970 being the performance target for software published through the Oculus store. I'm sure non-made for VR titles like Elite Dangerous, Star Citizen and the plethora of simulators will carry the usual feature/performance creep though over that period and give people the ability to stretch the legs of their Pascal SLI rigs.