Lol. Wasn't it Steve Jobs who really made this meme big in the context of design?
I like the subtle self-mockery in Newson+Ives
Ross Lovegrove always does a good job at this too 'I am the visionary, I will pave the way for the grand future'.
Sure it's all related to psychology. It's real hard to get out of a designer's ego sometimes
And I also know that it's most often the right hand that is raised for such poses, it's related to confidence/power. The left hand is the hand that shy people use to cover their faces with. The hand of insecurity, submissiveness.