Recently John Gruber wrote about the The Mac OS X Tipping Point and finished with this sumation:
You can’t appeal to all people all the time, but Mac OS X comes remarkably close. The old Mac OS, as insanely great as it was, did not.
I think what is so quickly forgotten about the transition to Mac OS X was Apple's against-the-grain assertion that they could build an OS the did appeal to beginner users and power users alike! This was NOT the prevailing wisdom of the day. I even remember seeing previews of the OS in which there were "modes" like standard user and advanced user. Simple Finder in Mac OS 9, ultimately was an outgrowth of this kind of thinking. Additionally, Microsoft was pursuing a dual code base strategy for desktop vs. server. Apple's insistence that you could actually build an OS that did scale from the grandma turning on a computer for the first time to a seasoned UNIX developer was courageous and spunky at the very least.
Recently, I have noticed a resurgence of the idea that the general purpose tool is by definition a less effective solution as compared to something more task specific. This hits home to me personally since I work on software that is used by a very broad spectrum of Mac users. There will always be tension when trying to design software to appeal to such a large and diverse audience, but simply factoring the problem into a "pro" and "beginner" products is the easy way out. You can make software that has general appeal and scales gracefully to a user's needs as they grow, it's just very hard to do! Difficulty aside, it is this kind of "scaling up" that defines what I love about great Mac software. All the core features are apparent and easily discoverable, but as you need more functionality, you effortlessly find them, almost as if the designers read your mind. Tools like these become transparent to your workflow and are a joy to use.