All of this is not entirely true. The Holy Grail in business doesn't always mean you have to do hardware and OS. One pure example of where it didn't work out as planned is Nokia. Grant it there is more involved that just this, but it just serves as an example.
Mobile is a very complex platform that involves many, many factors. In fact one of Apples biggest moves in our decade was to switch from making their own in house processors(their own hardware) and to go with x86 Intel Chips (someone elses hardware). Yes apple puts the hardware together, but its not just their own hardware. Even for the iphone and ipad, do you know who makes the CPU/GPU for Apple phones? They partnered with a company called Samsung, who also makes android phones.
Motorola isn't rumored to be making their own OS, they are, but the kind of OS they are looking to build is much different from the android or apple. From what I have read in the technology articles they are building a web based phones, which is still very much an untapped market and will most likely be different than a smartphone experience. Motorola has done a solid job with the android platform so far. I love my droid, the droid X is great, the Atrix is a smart idea, and the Xoom is a solid device(all my personal opinion) , I think motorola is one of the best android devices out there right now and it makes sense for them to explore new territory, like they did with the Atrix. Honestly the other companies like HP need to find a way to compete in a sea of android devices especially with great manufactures like HTC and Motorola, i think its smart that they choose to differentiate themselves.(again my opinion)
There is no right way to do a business. Whether you choose to focus in do good in one thing, or create an empire that does many amazing things, every business has their way to what they do. I am not dissing apple, android, microsoft, nokia, you or anyone. But please you cannot break down these very complex companies with thousands of employees, dozens of divisions across the world into simple black and white answers.