Microsoft even admitted that Windows 7 was largely based on Vista so I definitely wouldn't go as far as to say that "Windows 7 is not based on Vista".
With that being said, Vista is not a bad operating system, and anybody who says that it is a bad operating system is an idiot who jumped on the Vista hate bandwagon years ago. Vista made huge advancements in stability and security in the Windows line up. And admittedly it was far from perfect. And that is where Windows 7 comes in. Windows 7 was not written from the ground up, where as Vista was pretty close to completely rewritten compared to XP. BUT, Windows 7 is also way, way more than a service pack to Vista. Many parts of 7 were completely redesigned from Vista, for example, UAC, networking, backwards compatibility (within Windows API, I'm not talking about XP mode), graphics card driver framework + DX11, and most importantly memory management was completely redesigned which is what gives Windows 7 that feeling of hugely increased responsiveness compared to Vista.
But I do agree that it is pretty gutless of Microsoft to cut thousands of jobs when they just pulled in almost $15 billion in profit just so that their "numbers" don't look as bad.