I just don't get what's the main problem with Vista and 7?

All of the articles say that it's mainly because of the DRM implementation, and consumption of computer's resources.
I had no problem with DRM on my Vista, the OS just seems to slow down my PC alot due to my weak Dual Core Pentium processor and 2 gigs of memory.

And all that talk about someone messing up his Photoshop cracking attempt, plus some kind of sound card jam, and video quality being downed by the OS itself makes no sense. What's up with that?

Why did Microsoft even launch the Windows 7? Why couldn't they had just fixed the Vista up?

I'm confused.
Even thought of moving to Linux/Unix based OS, but got so used to Windows since it was my first OS ever to use.