Let's assume that a consumer device vendor does not want to pay more for hardware than what is required by their application. It's an assumption, but I think i

Let's assume that a consumer device vendor does not want to pay more for hardware than what is required by their application. It's an assumption, but I think it's a fairly reasonable one to start from. So the game boils down to "required by". For any non-trivial application (larger than x kB microcontroller) running on non-trivial hardware and using non-trivial software constructs you need non-trivial drivers. Those non-trivial drivers have to come from somewhere. That is the reason why OS's are scaled down (i.e. hacked to pieces) to fit the embedded market. When you start looking at constructing the software stack from the perspective of the requirements of the application, not those of the OS, you can leave a huge amount of gunk out since you know precisely what you will need. Why wouldn't you build your software stack to consume only the necessary amount of resources?