People make the mistake of thinking of Samsung as a single company - but it is not. Samsung's phone division is absolutely a hardware company, and so are the majority if their divisions. If they would be a software company, their Tizen OS would be in a lot better shape - but it's not.
And most Android manufacturers are hardware companies - their margins are too thin to support/maintain the software side of it. 90%+ of their R&D budget is hardware. It's the same as HP's computer division. No they are not a software company, they use MS Windows as the OS and make sure the correct drivers are present/integrated. This is exactly the same on Android. They buy off-the-shelve chipsets, integrate their drivers - which are developed by the chipset manufacturer - into Android, pour over some crappy GUI customization, in many cases developed by a 3rd party, and they're done.
And most Android manufacturers are hardware companies - their margins are too thin to support/maintain the software side of it. 90%+ of their R&D budget is hardware. It's the same as HP's computer division. No they are not a software company, they use MS Windows as the OS and make sure the correct drivers are present/integrated. This is exactly the same on Android. They buy off-the-shelve chipsets, integrate their drivers - which are developed by the chipset manufacturer - into Android, pour over some crappy GUI customization, in many cases developed by a 3rd party, and they're done.