Yep, but if Google just said "Here is our OS, you may put it on your products, but you may not deviate from principles set out by us" none of them would have taken up on it.
Mobile phone hardware is generally the same across most devices these days and most of the "Joe Public" don't care what's on the inside - so the software is where the manufacturers try to differentiate themselves from each other as a selling point
Mobile phone hardware is generally the same across most devices these days and most of the "Joe Public" don't care what's on the inside - so the software is where the manufacturers try to differentiate themselves from each other as a selling point