Yeah I can say that Mac OS X is an incredible OS. If I could run it along with everything that Windows has and have all the same compatibility as Windows does (DX 11 etc), then I would obviously be running OS X instead of Windows. The hardware optimization is outstanding, and the OS is very easy to use. I picked up a MacBook Air and I was instantly up and on my feet around the OS, sometimes I even accidentally try to use command+q to close things on my gaming rig, just out of habit.
The thing that I never really understood is that Macintosh laptops are actually quite competitive when you factor everything in. A MacBook air has 7 hour battery (with actual WiFi usage). The unibody aluminum design is unlike any other laptop that I've seen, and the sheer quality of every single little detail on the laptop is sheerly outstanding.
I don't think you really understand what the laptop is made for. The MacBook air is not made for gaming, all ultrabooks have Integrated Graphics (HD 4000). All laptops of this nature are not meant for gaming, rather web surfing as well as extreme portability. You think that the MacBook Air performs bad? It's going to perform just as poorly as those cheaply built Acer ultrabooks while gaming.
You seem to be using last gen's one, however even during the last gen, all competing ultrabooks had similar specs. Overall, I wouldn't call anything beyond 1- 1.5 inches thick a laptop anymore. Anything beyond that and it becomes much more difficult to carry around as it is heavy, and the battery life starts to suffer as well. Overall, I am very happy with my MacBook Air and can honestly say that there is nothing wrong with Apple's market strategy, and they are leading the laptop world for a reason. Their phones, are a different story though