So perhaps then it isn't the design of the software or the hardware, but the overall aesthetic. Both the Air and OSX are "pretty", but lacking in functionality.
OS X is basically a riff on BSD unix underneath. It's roughly as capable as any other version of unix so I'm not sure why you think that. OS X on the Macbook Air is the same as any other Mac. You can argue that you don't like Apple's operating systems and I wouldn't quibble but to say the software lacks functionality is just false.
If you don't like the hardware on the Air, I get that. It's necessarily a design with some tradeoffs that don't work for everyone. When you go as light as possible you have to leave some stuff behind. But that gets back to my point which is that Apple is really a software company. They put the software in a pretty box but (almost) nobody would give a shit if it ran Windows instead of OS X.
There's also an (undeserved) reputation for ease of use to consider, which ties back into the lack of functionality/flexibility.
Disagree that Apple's products haven't earned their reputation for ease of use. I've used Apple products on and off since the early 1980s and I've spent even more time with their competitor's products. As a general rule Apple products tend to be easier to teach to the technologically impaired, require less support and generally work more consistently and with less fuss than the competition. There are exceptions of course but on average it's usually true. That's not to say their products are perfect by any means. But having used, watched and supported others I have to say that the evidence largely points to Apple products being above average in ease of use.
When someone who is not a geek asks me whether to get a mac versus a PC or iPhone versus Android, I usually point them at the Apple product (budget permitting) because it will be less painful for them 95 times out of 100. When I converted my parents over to a Mac and iPad from Windows machines the number of tech support calls I got went from 1-3/month to 1-2/year. Furthermore if you live vaguely close to an Apple store it's a LOT easier to get support for a Mac than for most PCs.