Everyone seems to love Grey's Anatomy. I haven't quite figured out what they are so excited about.
Oh I love it  - Shonda Rimes is a create writer!
I'm not familiar with her work. 
She came up with the pilot, and now like what 11 seasons later she's still writing for them and is one of the producers.
That's impressive. It is hard to get a show to run for 11 years.
I agree -  it was designed to be racially diverse.  They did color-blind casting methods and that could account for some longevity.