Not only incompetent, I'm also: temporary, biologically fragile, incredibly addicted to sex, irrational, and vindictive. But even if I were none of those things, and in fact their polar opposites, I wouldn't be anymore powerful.
I'm curious as to why you think competence has any effect on the efficacy of the most powerful men on Earth? They are still operating within the confines of a very limited set of possibilities. Use your imagination. Envision all the things that could conceivably "be done" in this existence, and then compare that list to all the things that human beings can do. It's as if a Mother put her toddler in a play pen with blocks, and his "competence" was the ability to stack the blocks, whereas other toddlers were incompetent because they can only fumble around with them. Every toddler is just fumbling with blocks at the end of the day. If I ever give the title of "competent" to any leader in history or in the future (have yet to find one to whom I'd give it) it would be the leader who realizes they don't want to play with the blocks anymore, but would like to get out of the play pen.