4:3 (1.33) is a very good ratio. It's aesthetic and easy to get a nice composition in both horizontal and vertical orientation. It's also closer to square, which makes best use of optics (larger aperture, less vignetting, etc). All photography ratios that were actually designed are pretty close to 4:3 (1.33) : 4x5" (1.25), 5x7" (1.4), 8x10"(1.25) large formats, and 6x6cm (1.00), 6x4.5cm (1.33) medium formats.

3:2 (1.5) is not a "real" ratio. It comes from a desperate attempt to stitch two existing but tiny 4:3 cinema frames together to get better picture quality required for still. The biggest reasons it's still around is compatibility with legacy equipment and people being taught to treat 3:2 as "professional". Which is nothing but an acquired taste, as 35mm 3:2 was introduced as amateur format back when 4x5" was professional.

The 16:9 ratio of your laptop is also not an artist's choice. It was chosen as a compromise between TV ratio of 4:3 and highly panoramic (up to 2.35:1) ratios of cinemas. It was chosen to semi-acceptably display both types of content without pan&scan process that's expensive due to human labor. One of the major reasons of inventing a new ratio was to create immediately recognizable brand for HDTV, like first digital watches had numeric faces just to make them instantly recognizable. And it that regard it was very successful. Displaying still photography was probably not even considered, computer screens were almost exclusively 4:3 at the time.

The square works best for photography, not only because of artistic reasons (which are subjective) but also because cost of optics depends on diagonal. So square makes biggest bang for the buck. On the other hand, the cost of screen depends on area. That means that the longer the better, because you get less area for a given diagonal. 16:9 21" screen has about 20% less area than 4:3 21" screen. So you can market wide panel at same price bracket, but with 20% larger profit margin, that's every sales department wet dream. Sensors being silicon go same way as screens, cost-wise, but price of optics still dominates the cost of modern cameras.

Now, the bottom line is that none of those matter today. You can easily turn on crop on an expensive DSLR (eg Nikon D3, D4, D810 to 5:4 or Canon 5DS to 4:3) or a cheap point-and-shoot to 16:9. You have access to free editing programs to crop, you can even do cropping on your smartphone. In photography cropping is cheap and easy, and with digital it's taken for granted.

So why do we keep using 16:9, 3:2 and 4:3? Because those ratios became recognizable brands of HDTV, DSLR and pocket cameras, respectively. Except from consumer awareness there is actually no reason to stick to any of those. From purely technical point of view, our screens would be best at something like 2.35:1 and our cameras at 1:1.