Rob Halford argues:
"Black Sabbath absolutely invented heavy metal. I've read a lot of essays and such like about tracing it all back further and further. It's as though these writers want to claim the source, a bit like Dr. Livingstone and the source of the Nile. But as a purist metal musician, I can tell you— it's Black Sabbath."
http://en.wikipedia.org/wiki/Traditional_heavy_metal
So let me just straight, you think black sabbath are the "sole creators and founders" of heavy metal? A yes or a no would do.
I agree with him. It's not exactly a laughable opinion. Deep Purple sounds nothing like Black Sabbath - Black Sabbath. Ever.