When you buy a car, you are not only bying the actual vehicle, but also taking for granted you are able and allowed to access the whole travelling ecosystem with roads, gas stations, repair shops and so on. The car is your key to these services and if car for any reason is not able to access the ecosystem, it is not fulfilling it's purpose. Imagine a beutiful car that is not able to use normal road network; some enthusiasts won't care but for rest of us it doesn't sound like a good deal. At least it doesn't solve the problem of transportation.
When you buy a smartphone, you are not only buying the actual device, but also taking for granted you have access to networks, application stores, interesting media content, easy payment services and so on. Smartphone is the key to these services and smartphone without these services is like a car without the road. Some enthusiasts would love a great smartphone even if it is unable to communicate with the ecosystem, but that doesn't make a business case.
The magic equation is in this sense is:
hardware quality * software quality * services * price = terminal success
Nokia's recent problems have been in software and services, Apple's problem is the price and my recent Android experiences show that their problem is in hardware quality.