“The competitor to be feared is one who never bothers about you at all, but goes on making his own business better all the time.” - Henry Ford
I believe this is because his or her vision is so revolutionary it can't be stopped, only assisted. Take Steve Jobs, for example. In 1985, 14 years after co-founding Apple, he left the company after being "under-valued". Jobs then founded NeXT Computer, with $7 million. In 1996, Apple announced that it would buy NeXT for $429 million. The deal was finalized in late 1996, bringing Jobs back to the company he co-founded. He's the reason behind the majority of Apple's success today.
Moral of the story? A true visionary and an unstoppable force are one and the same.