3:2 used to be the standard screen ratio.
just look at your 15 inch CRT monitor.
the industry then went for 16:10 the so called "WIDESCREEN" at that time, and now 16:9
the industry then went for 16:10 the so called "WIDESCREEN" at that time, and now 16:9
Which is the reason the movie business invented wide-screen: To make their movies darn near unwatchable on standard television. HDTV went wide-screen to chase the movie business, which has in response pursued ever more extreme ultra-wide ratios (12:5 or 2.40 in not-insane notation) for their blockbusters, so even with a brand new wide-screen HDTV, you get letter-boxing and only partial vertical resolution when you watch the latest Batman movie or whatever.
Now there are some small movements in the direction of ultra-ultra wide-screen in the computer business, and it doesn't bode well. [1]
So it's Hollywood's fault that your computer screen has a stupid shape, just as its Hollywood's fault that it has a stupid interface (HDMI/HDCP), too.
[1] http://www.cnet.com/laptops/toshiba-satellite-u845w-s410/450...