Aside from Blake, the other obstinate man that comes to mind is Richard Stallman, founder of the Free Software movement, recently cancelled, a Macarthur Fellow and completely socially unacceptable person. I had some personal dealings with him back in the day, including having to rescue a few female friends from his attentions.
I'm not an admirer of his, either personally or for what he's done for software. But I have to respect his success in reshaping the world; he effectively created a massive hack on the concept of intellectual property, making software much more of.a community-owned thing that it would have been otherwise. The GPL is a very potent replicator; copies of it can be found inside of almost every electronic device sold.
What are the sources of this kind of world-changing obstinacy? I don't suppose it can be cultivated. And of course, it's hard to tell before the fact what kinds of obstinacy result in creative improvements and which lead to crackpottery, cults, or just plain stupidity.
Other icons of unreasonableness
Steve Jobs, of course
Ted Nelson is an example of someone whose obstinacy didn't serve him very well – he stuck to his guns about his vision but as a result couldn't get it built (despite being on the opposite end of the charm spectrum from someone like Stallman)
John Brown, the ultimate visual representation of obstinacy: