There's a reason Steve Ballmer screamed "developers! developers! developers!", and it's not that he forgot to take his medications. Developers are the people who create stuff that makes a platform attractive.
What Ballmer recognized was that if you have an environment that's friendly to developers, eventually you will have things regular users want. I'm surprised Apple doesn't seem to understand this.
Thanks to an accident of history (NeXT) combined with Apple killing backwards compatibility with OS9 down, they have a really developer-friendly API compared to Windows. On a purely technical level, Apple is far more developer-friendly than Windows.
They are doing their very best to shit that all away though, when it comes to the legal and backwards-compatibility side of things. That's one reason I doubt I'll ever spend my money on Apple.
1. the Win32 API is not the only thing to develop on Windows with. Personally, I find C# &.NET to be much more comfortable to program in than Objective-C & Cocoa.
2. There is no silver bullet. Some platforms are better at some things than others, but it's largely a matter of accidental complexity.