16:9 can't be equated to and is significantly worse than 16:10, which is worse than 3:2, which is worse than 4:3 (which is coming back on tablets). There were even 5:4 displays at one point (early days of desktop LCD, I still have my 1280x1024 19" ViewSonic VP191b).
Assuming 15" diagonals on all of them:
* a 16:9 display is 96 sq in and 7.4" high
* a 16:10 display is 101 sq in and 7.9" high
* a 3:2 display is 104 sq in and 8.3" high
* a 4:3 display is 108 sq in and 9" high
* a 5:4 display is 110 sq in and 9.4" high
As you can see, 16:10 -> 16:9 is actually the largest loss in surface area and second-largest loss of height (largest being 4:3 -> 3:2).
However if you're watching a movie, the 16:9 has 100% coverage for 16:9 and 75% coverage for Cinemascope, every other format gets lower in both relative and absolute coverage, down to 70% (77 sq in) and 53% (58 sq in) for a 5:4.
> How the hell did people think it was a good idea?
Black bars on movies, better view angles in FPS, and cheaper.