I'm disagreeing that a noob can work a complex piece of software successful or would often want to. The people who buy DSLRs today are probably the 5% of people most interested in photography. That's already a pretty motivated group. Maybe not motivated enough to crack a book (though I don't understand why people selling a $500 camera can't have a website that teaches the basics well) but motivated. Most of Apple's customers are going to be substantially less motivated than the people who buy a DSLR and never take it of program.
I think they can go noob to moderately interested amateur. But I think you are still overestimating the market.
You are right though that good defaults allow for programs to work well with lots of features. Word (a rather complex program, that everyone knows how to use) being a great example.