Go back and re-read exactly what you wrote and you'll notice you basically answered your own question. 😉
It's a marketing strategy to get more people to get a Mac. Firstly, Windows 7 has a wide adoption rate so why support a system that people will inherently remain on against a system that not everyone is happy about such as Windows 8? Also Windows 7 is now old and Apple has supported Windows 7 for quite a while.
In your rant I guess you didn't check Apple's website that stated that iCloud Drive requires OS X Yosemite and they stated "Some features require iOS 8 and OS X Yosemite.". So Mavericks users are left in the cold. You think they're going to support Windows 7? 🙄