DSLRs + lenses are seemingly the one and only product category within consumer electronics...
Last time I checked, dSLRs and lenses weren't purely 'electronics' - they have optics, right? Sure, modern cameras depend on electronics, but so do cars, toasters, etc. If I want a car with 6 cylinders instead of 4, or a toaster that toasts 4 slices instead of 2, I expect to pay more. If I want a lens with a faster aperture, or a camera with better build and features, I expect to pay more, too. Have I been brainwashed by Canon's marketing department? No. I just don't always expect that more+better+faster=cheaper.
Regardless, the market will ultimately determine the price. If sales of the 5DIII slow, Canon will drop the price. Simple economics.
Yes, but haven't you heard? Sony's making an 8-cylinder Nikon toaster that burns 50,000 pickles in 1/250 second. Unless Canon gets their act together and releases a firmware update that confirms each shot I take with a blow job, I'm going back to shooting Brownies. In the head, with a shotgun.
Seriously, I think it's pretty obvious that all those complaining about how miserable either the 5D or the D800 is don't shoot anything more demanding than a brick wall and think that $4K is a lot of money.
Now, don't get me worng. Lots of photography -- the majority of serious photography, and the overwhelming majority of all photography -- isn't more demanding than shooting brick walls. Street photography, for example, though damned hard artistically, is mostly people in front of brick walls and technically only really needs a Nifty Fifty on a manual camera with some decent black-and-white film. And $4K is
a lot of money for most people. Heck, most of the people on the planet don't even spend that much in an entire year.
Modern weddings and sports, on the other hand, to name just a couple examples, need a bit more than HCB's Leica (or the Pentax ME-Super I've got stashed in a closet somewhere), at least if you want to produce what the clients are expecting and willing to pay for. And if you're a professional photographer who's agonizing over the affordability of a $4k purchase (rather than evaluating how long it'll take you to recoup the expenses and turn a profit), you're not going to be a professional photographer much longer. For the non-pros, if you're comfortably middle-class and this is what you spend your money on (as opposed to cruise vacations or big-screen TVs or golf or whatever), it's either not that big a deal (depending on how comfortable your middle-class status is) or you patiently scrimp and save until you've set aside the cash to buy the sniny new toy you've been wanting to play with.
And if all you're doing is whining about how you can't figure out why somebody would speed FOUR THOUSAND DOLLARS on a camera that doesn't have some random gimmick you read about in the competition's sales brochure...well, I've got news for all y'all.
The camera is the cheap, disposable part of a photographer's kit.
It's almost an afterthought, really, when it comes right down to it. Most photographers will not only have multiple bodies, but a whole bag full of lenses, and it's not uncommon for at least a couple of those lenses to cost multiple times as much as a single camera, a few of them about as much as a camera, and several of them more than a top-of-the-line point-and-shoot camera.
And then there's the lighting and background equipment, the computer and software, the printer and ink (and not only can the printer cost as much as a 5DIII if you print big enough, but so can a complete set of ink cartridges), the color profiling gear, and on and on and on and on.
This is not a cheap profession / hobby, and whining about the cost of a 5DIII body comes off every bit as silly as somebody wondering if you really have to put high-octane gas in that Ferrari, especially since it gets less than half the mileage of an econobox.