In a few years time, most people will have forgotten the days, not so long ago, when Apple would take about 10 iterations to eventually make their OS's totally rock solid. Leopard and Snow Leopard each started out really buggy, but by the end of their iterations they were totally rock solid. All that will change. Now, with a new OS each year, and only 5 iterations for Lion (so far), we're leaving the days when Apple would keep going until the OS was totally solid. We're now entering a post-Jobs era where, under Cook, near enough is good enough, then on to the next best thing. It's a consumer orientation focused on making tons of money, rather than pride of craftsmanship in the OS.
Back in the old days - I mean Leopard and Snow Leopard - I could basically sit it out on the 9th or 10th iteration of the OS, waiting for about a year till you early adopters beta tested for bugs, and then I'd join the game when the OS was mostly de-bugged. But now, these new OS's don't seen to get past the 5th iteration.
I'd say, if you study corporate history of the rise and fall of corporations, I'd give Apple about 12 years. In that time, it could go from media star to total has-been.