I have had plenty of experience of computers, projectors and other electronics failing, but I have to encounter any window suddenly become opaque!
If a windowless plane DID have an electronic failure, something which seems relatively common on complex modern aircraft, the dark interior would be pretty unpleasant.
Copper is needed for wiring and due to demand around the world its cost is increasing dramatically, glass remains relatively cheap and plentiful.
How long would it be before many passengers started complaining about projected views of the outside and demand wall-to-wall movies? Then no-one would be able to see out.
Concorde designers looked at the problems 50 years ago and decided that windows were a good idea despite their problems, and I think they made the right decision!