You know that windows have serious flaws, but not those are the ones that got exploited most of the time.

The windows alone is useless. What to do? Play Solitaire whole day ?

You have to install programs to do you work, to play music, movies, etc.

Every program, every software can have serious vulnerabilities. It is hard to keep track of them. This is why they are keeping publishing updates again and again.

They want to keep their software secure  and this is why they make changes. But it is a slight chance that they will finaly have a flawless product. The perfection is far.

Despite all these, you can keep yourself a little protected. Update the software and use a firewall.