Over the weekend I had lunch with a long-time professional photographer and Mac user who is also a beta tester for Adobe's next-generation photo editing program, Lightroom. I asked for a comparison to Apple's high-end photo program Aperture and he said "There's no comparison. I don't understand why Apple shipped Aperture. There was a hole in the market for Final Cut, because Adobe let Premiere slip, but nobody was really looking for a Photoshop alternative."
The explanation for Aperture is simply that it's in Apple's (and Steve Jobs') DNA to want to do everything themselves. Sure, there's a big ecology of add-on Apple software and hardware, but when it comes to the core products, Apple wants to control it all. Clearly, photo editing software won't make or break the company (already some of the Aperture technology is seeping into iPhoto, which is good for everyone). But the Must Invent It Here attitude is a broader concern--especially in the world of media playback.
How might Apple blow its commanding lead in legal digital audio and video distribution? By not playing well with others, and thus creating an industry demand for alternatives. The fact that Steve Jobs has the power to tell the record labels, nope, it's still going to be 99 cents a download, now please go away, is not something that makes content owners happy. The fact that the rest of the consumer electronics industry is locked out of the iPod hardware market (except for peripherals) doesn't make them happy, either. In the media sphere, those are two mighty powerful constituencies to annoy.
Apple's go-it-alone strategy is why, in part, it possesses a single-digit share of the world PC market when 25 years ago it had a shot at owning the space. Now, Apple's biggest software competitor in the digital media space is Microsoft, which is happily pursuing the same strategy in the media world that let them own the PC market: make somewhat clumsy and inelegant software that nonetheless runs on all kinds of hardware and will support all kinds of media distribution platforms.