Wouldn't it be more expensive to have the laptop be machined out of magnesium though?
Koing
No, magnesium is usually moulded in terms of these industrial processes. More efficient structure, but again not as good looking when you're looking at a moulded piece of magnesium compared to an equivalent piece of machined aluminium. Again - it's about looks, machine aluminium has that kind of more industrial look about it while a piece of moulded magnesium plate looks... well, looks like a piece of moulded plastic. Thing is though, a wafer-thin bathtub structure of magnesium with the above process will withstand a beating far better than the equivalent structure done by Apple.
Having said that, Microsoft has done a really good job of making moulded magnesium look like machined aluminium in terms of how people react to this sort of thing.
Actually a cheaper process as well in reasonable numbers - though I'm not sure about (as I again referred to Apple's hell bent concentration on this process and their focusing on a very small number of different structures across their model ranges) Apple's volumes now.
Magnesium also has some interesting work going on it in the durability stakes, something which Microsoft pioneered in the consumer space as well with the Surface. Nitriding is a process where you basically vaporise a target and blast it at a base metal, to create a hard crust (beyond anodisation). Nitriding as a process has been around for a while in the form of e.g. suspension stanchion coatings and other high-wear surface treatments, but nitriding low melting point metals like magnesium is pretty new. Unfortunately MS has been working the kinks out of the process basically as a public beta over the last two years. The reports of Surface flaking you can undoubtedly find are instances of the TiCN (titanium carbon nitride) coatings delaminating from the base metal.
On the flipside, as usual Apple actually brought near-zero innovations to the table with the Air onwards, but applied marketing and re-spun existing proven processes to appeal to the abovementioned joe. They do it hellishly well though with a huge eye for detail, even the biggest non-Applezombie has to give them that. And with all the companies they've taken over / licensed stuff from recently, maybe there's a chance they'll actually start doing something genuinely innovative as well, who knows... but even if the next process has no innovation, they'll surely spin it so that the Applezombies will claim it's some major leap, Pavlovian-style, again. Watching what pathetically passes for the tech press swooning over the Air's top shell back in '08 was the most amusing, and also the most damning, thing I saw.