→ Vista's Real Problem: It Wasn't Released
It was just not executed well, not the product itself, but we went a gap of about five, six years without a product.
This illustrates one of Apple's core strengths: iteration. Of course the iPad 1.0 is not the final iPad. Give it a year or two and of course all iPads will have a camera (or two!), fancier software, higher resolution(?), maybe even weigh less. But that doesn't stop Apple from shipping something polished now. Apple is looking at certain highly desirable features, and saying "No, not now. Later." (The funny thing is how the world hears "no" and doesn't think "later, certainly.")
Microsoft failed to do this with Vista: they had to "finish" too much and couldn't make the tough decisions about what to work on in the short term (12-18 months) and everything snowballed and got pushed out 60-72 months. Arguably they got into this position with poor technical/architectural decisions years ago (registry, permissive security policies, etc.). Apple's Near Death Experience (and acquisition of NeXT) forced them into a rare position where they were able to rewrite Mac OS from scratch---Mac OS was that unsalvageable (and it didn't hurt that NeXT had worked on NeXTStep for a decade the whole time).