Nobody is suggesting 4:3. However, look at those pictures and of the display in-particular. First thing you notice? The massive bezel at the bottom of the screen. On a Macbook Pro (with its 16:10 screen), that space contains extra screen instead of plastic. Would you rather have a fatter plastic bezel, or more screen real-estate? 16:10 is still widescreen, can handle side-by-side pages fine, and often has the same horizontal resolution as 16:9 panels, but has more vertical space and resolution. Given that vertical space is often chomped up by the task bar, title bar, menu/toolbars etc, an extra chunk of vertical space there makes a *big* difference to usability.
Sorry, but every time I see a supposedly professional machine with a 16:9 screen, all I see is a laptop display chosen for its cheapness rather than for its functionality. That's why 16:9 screens have taken over most laptops - because they are cheaper to produce (due to being the same aspect ratio as a TV), that's the only reason. And if I'm splashing 2 grand on a professional machine, I want a display chosen for its quality and suitability, not its cheapness. Something that Lenovo, Dell, HP etc. all fail to grasp still...