Obviously you are not a Hardware Engineer. Consider for a moment the variety of screen sizes. Now let's mix in the variety of DDR configurations, modems, coprocessors, bus controllers, LTE modems, WiFi Modems and General Purpose Processors, cameras, video codecs, storage memory units - all low price contenders bought in bulk. All running an OS built, designed and sourced by a dis-interested 3rd party.
How efficient do you suppose this is? How secure do you think it is? Anyone, at any time, can write any chunk of code and access any part of your phone and do anything they want. Perhaps that photo editing software is also hacking your bank? Perhaps every personal contact is now being used as an identity theft hack?
Your personal information is now far more personal than ever. Where you walked, what your pulse rate was, how fast you climbed those hills. When you stopped to rest. How long. Perhaps your employer is looking to do a layoff; and you just are not as healthy as he wants. Now he knows your heart rates, your rest pulse rate, how fast you walk etc. he can find your Dr visits from your calendar and your meds from your phone. If you log your blood pressure and glucose, he can get that too.
That doesn't begin to cover your texts, social media, phone calls or email. All that is wide open in Andeoid. Google makes no secret that they monitor this. When a product or service is free; the product is YOU
Oh, I’ve developed hardware! And it’s been all over the place...
So how were PC guys able to pull off the wide assortment of hardware and configurations yet have a single OS support them? Curious, eh? Maybe Google isn’t a dis-interested as you think, perhaps they built and extensible OS that allows for support for a variety of hardware?