Why is that on all movies you see today every notebook that shows up is a macbook?
Does it really correspond to reality?

A very true observation.
From my pov, it doesn't correspond to reality. Probably mass advertising.

not "probably", it is basic product placement, if you see a real-world brand displayed clearly in a movie you can be 100% certain that the owner of the brand paid good money for it and they want maximum exposure then (So if Apple buys product placement in movieX you probably won't see their competitors in it, Samsung, Dell, HTC, Sony etc show up in tons of movies aswell but obviously a big marketing heavy company like Apple will get more exposure than many of its smaller competitors) (And ofcourse, Sony movies(Skyfall, Spiderman for example) tend to be flooded with Vaios and Xperias)

I would argue that sometimes it's also the director's choice. For instance, if you're directing a hacker movie and your hackers are using Windows, people watching the movie won't take them seriously because it's common knowledge that Windows is far more vulnerable to hacker attacks than Linux or Mac. The director will want the hackers to use technology not in common use to give the hackers a more professional, or should I even say "god like", appearance.

(Before you launch technical arguments in an attempt to counter my statement: I'm talking purely from the point of view of the OS' impression on general public, and not claiming that Windows is an inferior hacker's tool. With that said, if you were to do your hacking business on Windows, your hacker peers will laugh in your face).