Looking back at that video, it's quite unfortunate that Microsoft once again used a car analogy. Suggesting that a functional, but bland looking car is the equivalent of Windows 7 etc and Windows 8 is a whole new paradigm of excitement, simply shows that they were after bling and not something exciting that was also functional. A Camry and a Ferrari are both functional in how they work, but one is bland and the other is exciting. Windows 8 is not a Ferrari.
But the conversation that Windows 8 has not only been its polarizing design, has been touch computing, the use of tablet PCs, ending skeuomorphic design in UI design, the expansion of the Natural User Interface, different app models and even using technology to make non-touch PCs to have touch input like the Microsoft Touch Mouse or the Logitech touch pad and mice; and resulting in new PCs like the Surface Pro or the Lenovo Yoga or the Asus Tachi as well as the convertible form factor and taking traditional form factors and making them touch enabled.
The steering wheel reference I'm making is not really metaphorical, where the mouse is the wheel. But it's literally the same thing as driving, your arms are extended away from you for long periods of time. Of course, you're holding onto something, but that kind of happens with a touch desktop. Depending on how you sit, how high you sit, and how close you sit; your elbow might actually end up on top of your desk. Normally, there are guidelines to how you're supposed to sit, but usually not many follow those guidelines out of comfort. Using touch on a desktop, you have to move away from the guidelines to using a PC (the way you're supposed to sit that most people again don't follow as it's not too comfortable either) to using a touch PC. Driving a Camry is different than driving a sports car like a Dodge Viper or a Ferrari. A Ferrari and Viper have more attention to detail and details you may never see versus a Camry. Windows 8 is not a Camry, but not so much of a Ferrari either. It's a four door Dodge Charger.
The example is wrong. A car requires a predefined mould because there are fundamental engineering, functional and design rule aspects that must be adhered to in every car. Once those requirements are satisfied, you can pretty much change other things to your hearts content. In some respects, Microsoft decided to ignore some of those fundamental requirements and do their own thing.
It's like removing the steering wheel and replacing it with a joystick. Yes, a joy stick can be used to control a car, but the results will be very unsatisfactory, as that's not what people are used to using. How well do you think a car would sell if it was steered using a joystick? That's effectively what Microsoft has done.
Also, there's nothing new about touch controls in computing, it's been around for a long time; all Windows 8 does is offer an extension of that in the Microsoft environment. They are playing catch up, but alienating their traditional user base in an attempt to entice a new group of users. Windows has been a cash cow for Microsoft for a very long time, for good reason, but once they remove the reason for that traditional user base to stick with Microsoft, then the cash cow will start to dry up. Then Microsoft will be between a rock and a hard place.
Windows 8 isn't like blowing out the mold of how to design a car, it's blowing the mold of how to design a product that many others have designed, a Desktop based UI with icons and window chrome from chrome OS to mac OS, and reinvented that into a Start Screen with live tiles.
Interesting you mention touch controls being around for a long time. Electric cars have been around since the early days of the Ford Model T, have been developed in the '70s, experimented in the '80s, refined in the '90s, and are finally at the verge of being mainstream today. If you took away ICE engines from many people and replaced it with an electric car, they will be alienated by it. Grease monkeys (myself included) will be upset by that as a complex and beautiful thing as an engine is replaced by a motor and battery. But in the end, many people will enjoy the responsiveness of how fast an electric car can get up to in six seconds, the quietness of it, and ease and cost effective repairs. Auto makers will adapt and innovate and research designs of cars and how to make electric cars better. It'll get to a point where if an auto maker isn't building electric cars or not putting a lot effort into it and thinking electric cars are a phase, they'll die out or become a niche product for a small group of people.
Going from last to first, people wouldn't and are not alienated by electric cars, as everything in an electric car replicates that of a traditionally powered car. Without badges etc, you couldn't even identify an electric car from any other when at a standstill and turned off. And they replicate traditionally engined cars for the very reason so as not to alienate potential buyers.
As for the first part, the car industry is huge and varied, there is room for white goods (aka Camry) and bespoke (aka Ferrari) and anything in between. The car industry provides vehicles for many an varied uses, be it utilitarian or completely impractical but enjoyable. Everyone has a choice for what they need or desire.
An OS, in itself, does nothing. An OS is designed to support and provide an environment where other programs can function. When an OS doesn't provide that environment and support, but imposes its own requirements, it ignores its prime objective. To ignore or belittle the needs of the traditional user base, is fraught with folly.
Yes, the auto industry has a lot of different niches for needs or demands. The VERY same with PC hardware and Windows. For example, I'm building a desktop that does literally everything from Xbox gaming, being a home server, my telly, media center, gaming rig, and some other things. That partly relies on the hardware. The software is what matters. Windows 8 is what I'll be using on that. You might use Windows 7 as you feel that's proper, but Windows 8 allows me to do more with my hardware. If I want to use apps that would be on my Windows Phone to be on my PC, I can do that. If I want to switch over to the Xbox part, I can. If I want to create a pretty decent Excel spreadsheet, oh yeah. My point is, is that Windows 8 is much like Windows before and more. It can be arranged for different niches and demands. If you want Windows 8 to be primarily gaming, you'd fill a Start Screen full of games. If you want it to be primarily Desktop based, your Start Screen would be filled out with Desktop apps and locations. If you want Windows 8 to be internet content based, your Start Screen will be filled out with Windows Store apps. If you want to do all the above, you'd have all that in the Start Screen.
There really isn't ANYTHING in Windows 8 that doesn't offer or provide an environment to support programs and allow them to function, nor does it impose requirements (other than on the hardware to keep a consistent user experience but this has been Windows since ever) and doesn't ignore it's prime objective.