A friend had a Ford Escort Convvertible XR3i - or at least thats what I think it was. It too had a heated windscreen and as has been pointed out they were very expensive.
One morning he went out to his car and found some scumbag had stolen the windscreen!
However they failed to notice the expensive leather jacket on the back seat with a well-stuffed wallet in one of the pockets
Until someone pointed out the wires in the windscreen, I never noticed them, but after that I couldnt stop myself trying to focus on them rather than the road ahead!
Aircraft have heated windscreens that get really hot
- but there are no wires - instead the screen has a thin, transparent, conductive film over the surface to which a voltage is applied which evenly distributes heat over the entire panel. The window film is usually a Indium tin oxide, or gold - far better than a windscreen full of wiggly wires!
This design probably isn't used on everyday cars due to cost.