- allow a simpler and cheaper camera design by eliminating expensive to assemble moving parts and removing the requirement for seperate AF and metering sensors
EVFs are more expensive than OVFs, if the EVF is decent.
- offer a larger and brighter image than most APS-C viewfinders
- allow more freedom with lens design by allowing placement of rear elements further towards sensor
This isn't an advantage of an EVF, it's an advantage of removing the mirror box, and only if your entire lens system changes.
- allow more shooting information to be displayed, e.g. magnified focus, focus peaking, zebras & real-time histogram
I consider that a disadvantage, as it's distracting. I turn it all off on my EVF cameras. The only advantage is for manual focus situations.
- image lag
- contrast range
Zero power draw as well.
Of all these, the cost reason will be why manufacturers will eventually move to EVFs across their whole range, except maybe their flagship sports/action cameras.
Since that's an invalid reason, I don't see why they'd bother to make everything else worse.
I'd like a hybrid EVF/OVF using the EVF for video and manual focus situations only.