...any serious or professional photographer who relies on actual real-time update and large, full-detail viewfinder won't be moving to EVF any time soon. There is just plain and simply no replacement for a prism.Wouldn't a serious photographer know the benefits of a waist level finder and consider the prism a technical detail rather then a dogma? The viewfinder of a 1Dx feels rather tiny compared to a 645, and don't even think about anything large. And if one compares the mandatory ~40ms release lag to the less then 10ms you can get electronically...
Guess it will take some time for the pros who now shoot tethered and use the computers screen as VF to accept anything else then a prism.
Just think of switchable glass, a surface that changes from clear to mirror depending on a static voltage applied to it, that allows for a hybrid viewfinder with a user selectable blending ratio. You'd still be limited in VF size though.
Well, you've switched contexts from sports to studio photography, where use of a tethered laptop or computer is quite normal. The original context was sports and action photography, where the OVF and a dedicated AF unit still rules as king.
I would take my tethered Surface Pro any day over an EVF, though. There was a thread a while back where I computed the necessary pixel densities to make an EVF screen be high enough resolution for the average 20/20 viewer at a 25mm eye relief such that pixels were invisible. For 20/20 vision, you would need just over 5000ppi. To accomodate users who have better vision, or users such as myself who have 20/10 vision with contacts, you would need an insane 12,000ppi. With the average size of a viewfinder, 5000ppi is pushing the limit of how small pixels can be and still be transparent to light. At 12000ppi, you are already cutting off the longer frequencies of light, and therefor only able to pass greens, blues, and violets. And that isn't even touching DR, or the fact that even if the EVF supports high bit depth it is still limited by the camera's DR.
The day will never come when an EVF (or, for that matter, a tethered laptop screen) becomes superior to an optical view finder for action photography. There is no substitute for a truly real-time, high resolution, bright, optical prism based viewfinder. For action. Studio work is a different matter, but as you say, people have been tethering and using huge screens for a very long time in that industry, so they still have a superior tool than an EVF.
Not really sure what you mean about switchable glass. Sounds like you are talking about the piezoelectric effect, however I am not really sure how that is much different than what Canon already has with their transmissive LCD that overlays their current viewfinders. It is fairly simple right now, but there is no reason Canon couldn't drop a whole ton of information into that screen with a selectable mode button...imagine seeing the histogram as black bars in the viewfinder...or the electronic level...or, any amount of information you desire, and still always have full use of the OVF.