Apple was well aware of the netbook segment -- they chose to ignore it. Their "competitor" to the netbooks, the iPod/iPhone line, has been doing extremely well. Ubuntu hasn't succeeded in gaining traction in the portable device market, but you don't consider that a failure.
People like taking potshots at Apple by ignoring what Apple actually does, and perhaps that's deserved because Apple has a reputation for unflagging arrogance. It bugs me, though, when people make statements like the OP, because Apple and Ubuntu aren't doing the same thing whatsoever. Ubuntu has its goals, which include netbooks. Apple has said again and again: they understand it's an open market, but they don't want to release a product until they're certain they can make something of their accepted quality level. Meanwhile, they've made the iPhone into a miniature netbook with the App Store, and a lot of people are using it as such.
In the end, it's all very silly. The people who think that Ubuntu is cutting edge conflict with the Apple users who think the same, because we two camps use different definitions of "cutting edge". Can we stop bickering about it now? There's room enough for us all to hold hands, kiss, make up, and go back to tormenting the Windows users. (Joke! Don't shoot me.)
