Break what? The markets still growing, there are always people entering the smartphone market. Good hardware is important but Apple's ecosystem also attracts a lot of people. Most people don't buy a new phone every year, they wait for their contract to expire. So people with an expiring iPhone 4 contract will get all the new features of the 4S plus the larger screen and whatever else comes. Lots of people complained the 4S wasn't a big upgrade but it was a whole new experience for me upgrading from a 3GS.
And they may have had 2 years since the iPhone 4 but they released the iPhone 4S and iOS 5 in the time.
Why do you want a fingerprint scanner and breathalyser? Those things would disappoint me, as most people have almost no use for them. Why would I ever need a breathalyser on my phone?