Agree, except part of the Air's aesthetics was its extreme portability, an actually useful feature. The problem was then it was far too slow to be even a main road warrior machine. But it was a technological feat just to get it that small in the first place, much less worry about performance.
In fact, the Cube even had some high technology behind the looks. The kind of molding technology to make that case was invented by Apple, and the system was carefully designed to allow chimney cooling without fans. It's not like the standard, stick a fancy plastic faceplate on a box and call it "design."
And, yes, the 20th Anniversary Mac was just for show, a "here's what we can do" vision thing. I was surprised Apple didn't make it a limited edition in the first place.
They did, just not limited enough. They made 12,000, and had to cut the price from $9K to $2K before they finally unloaded all of them.
I have to disagree with your slowness characterization of the Macbook Air. When the Macbook Air came out on January 15, 2008, at 2.9 pounds and .76 inch thick, it was far faster than any other sub-notebook on the market at 1.6GHz... and it would run Windows XP, Vista, and later Windows 7. The offerings from the other companies at the time in the same class were generally 1Ghz or slower. Although not a speed demon, with 667MHz DDR2 RAM, and a Intel P7500 Core 2 Duo processor, it easily competed with main stream notebook computers.