I don't think all the cool tools are coming out for the Mac but it's undoubtedly skewed towards it. The reasons for this are a mix of cultural, social and technical, along with momentum.
Speaking for myself, when I was getting into serious programming, it was right in the heyday of the Delicious Generation (Delicious Library, Disco, AppZapper and more). Back in the 10.4 / 10.5 days, eye candy and ease-of-use were the top priority. Some notable apps came out and they in turn inspired other developers to follow the same path - a polished user experience is absolutely vital. This creates a self-perpetuating cycle, where the existence of such apps creates fans who dream of making apps like that (I'm one of these).
My co-workers who run Windows hate me for this; every few days I get super excited about some awesome tiny tool that saves me time, and explain in rushed tones how awesome it is, only for my co-workers to groan once again when I sheepishly mention its "Mac only"... on the other hand, they have some awesome apps I don't either!
As I recall, folks used it for inserting circuit diagrams into usenet posts. I've used it for sticking skeletal hookup diagrams into my microcontroller source code. When I write a code to access a particular device such as a specialized chip, I like to include in the comments a diagram that will at least let you demonstrate the code.
As an aside, the cool toys are coming out for this "operating system" called Python. ;-)
