Please read slower. I haven't said that it isn't possible to have a mechanical solution.
But look at the alternatives between Sony and Canon. Canon have a big offering of good lenses with very good IS. Sony hasn't.
So Sony is way more motivated to spend a huge amount of time implementing and testing a mechanical IS in the camera, because of the even larger amount of time and cost to release a new set of lenses with IS.
One disadvantage with IS in the camera is that it doesn't work in the view finder so with big tele lenses it will still be hard to hand-hold and aim carefully.
Another thing here is that a small shake with a wide-angle lens hardly gives any camera shake in the photo. While a small shake with a big tele lens gives a huge blur in the photo. IS in the lens works better because it is designed specifically with the relevant focal length in mind. And while sensor solutions normally just shift the sensor sideways, an optical solution can twist the lens element when you twist the lens.
Shaking the sensor easy? Remember one thing. The sensor is an electronic component designed to read out hundreds of megabyte of data every second. Shaking it is a bit more complicated than shaking a piece of glass that isn't attached to the rest of the camera equipment with any electrical wires. If the electrical connects to the sensor fails, your camera is dead. If the IS in a lens fails, you can switch lens. Or you may even be able to continue to use that lens, but without IS.
A sensor failure in a $100 camera isn't an issue. Having the same in a $3500 camera just after the warranty ended, would be a much bigger issue. The sensor isn't exactly the cheapest part in a high-end DSLR.
So no, your "shaking the sensor should be cake in comparison" really sounds like you have ignored a couple of steps when you made your conclusion.
1. In body IS and lens IS can and should be mutually exclusive.
2. shaking the sensor has existed for over a decade, maybe longer. It's not new tech, especially for a company like canon... it's cake to them.
3. Dont see how a shaking sensor would be less reliable than a slapping shutter.
Your not saying that Canon's missing the boat? Read the thread title again, and please remind me what the goal with this thread is about.
no I'm not, I'm saying that canon IS the boat, they can get away with skimping features != missing the boat (falling behind)
clearly canon is a strong company, and I dont think they are falling behind in terms as sales and market presence compared to nikon or sony.