Re: Door mirrors...
"You have no stereo vision at the range of a car behind you. "
Not technically true. People instinctiely will bob their head about when looking at the mirror. This has the effect of increasing the parallax, allowing people to more accurately judge distances. Most people do this without noticing , but it is somethiing that cannot be done on a 2D screen.
It is also the trick people use with animated gifs, allowing you to perceive a 3D image in a 2D environment. (see here as an example: http://www.maddocman.com/wiggle-3d.htm Not my site, just the first on google search)
"The vision system can have distance measuring (Radar, lidar image processing) and can highlight cars in your blind spot"
So now we are replacing a cheap, simple and reliable system, with two complicated, computerized and expensive systems? And this is considered an improvement?
"If you have the screen anyway then the cost of the camera is negligble and less than the lifetime cost of fuel used by the extra drag."
Where would you put the screen? Most people look left when they want to manuveur left, having the screen in the centre would be worse than before. I would imagine there would need to be two screens (left and right, roughly where people now see their wing mirrors), in addition to whatever screens the rest of the car has.
"Wing mirrors also get broken and aren't replaced until the next MOT (or never over here) they are probably less reliable than cameras"
I disagree with that, I have rarely seen broken wing mirrors, most of them are really sturdy, you really need a lot of force to break them. I think less than 1% of the cars on the road I have seen had broken wing mirrors.
Not to mention a broken wing mirror is easily seen by others, so they can say "Ok, person might not be able to see me on that side of the car, better act accordingly". It acts as a visual sign. There is no way for other drivers to tell if the wing cameras are working or not, including police (who can pull you over if you have a broken wing mirror, at least here in the UK).
"Big advantage on no wing mirrors is reduced noise in the back"
From what I can see, replacing wing mirrors with cameras provides two minor advantages, while giving a boatload of disadvantages.
We are replacing a simple, reliable system, with two expensive, complicated less reliable systems, that will be:
a) more expensive to buy
b) more expensive to repair (coupled with others not being able to tell outside the car, less likely to get fixed unless it becomes an automatic MOT failure)
c) more dangerous (not only due to loss of ability to tell distance of car behind and because others can't tell if you can see them, but also because it is easier for cameras to be blinded by bright lights, or get dirty, or fail)
All for a minor gain in fuel economy, and less noise in the back? I would argue that as cars get more and more complicated, they last shorter periods of time. Pretty much the first things that go on second hand cars are the electrics. Engine/mechanicals are last, usually (unless you bought a pup that was badly treated).
As cars get more and more computerised and interconnected, they become so expensive to repair, that their lives will be shorter than the old cars. Some people already own a car only for the duration of the warranty, then sell it due to the expense (everyone complains about rip-off mechanics though, as if the job is easy and simple on new cars. It is ruddy awful working on new cars).
Cars like these will not last long, and will be scrapped and new ones built more often, becoming more like a consumer good rather than a durable good. This is a huge waste of energy IMO, which dwarfs whatever the fuel consumption improvement you would gain by getting rid of of the wing mirrors (especially as the drag can be reduced by smart aerodynamics, I seem to remember reading that some sports car actually had the wing mirrors improve downforce).
Really, complexity breeds problems and failures. It takes a lot of thinking and effort to make something simple, elegant and functional, along with an understanding the law of diminshing returns when it comes to application of technology.