The problem is, you can never beat some aspects of an OVF with an EVF. How are you going to improve on zero lag, zero power use, virtually infinite dynamic range and color gamut?The human visual system already has lag, and some EVFs are getting quite close to human lag.
If they are the same, then the EVF is doubling the system lag.
Human vision lag is, if I remember correctly, about 100ms. Current best EVF lag is, if I recall correctly, about 30ms. That could easily come down to 10ms in the next few years, and I doubt you could distinguish a 10% increase from OVF.
As for the DR and color, that's precisely why I want an EVF: I want to compose using what the sensor can see, so I have a better idea of the final image. This is another plus for EVF.
Sorry, EVFs don't show that, they show the in-camera JPEG conversion, which is way, way smaller than what the sensor can see. I post this example often:
The fact that they don't currently doesn't mean they can't very soon. Do you ever use Live View? I'm still unpersuaded that, aside from battery life, there are any serious problems with EVF that can't be overcome in a very few years. And, when that happens, EVF will be indisputably superior to OVF.