Seems like to do so he might leave video games entirely
"Ideally I would like to step out from the Metal Gear franchise as a producer and dedicate myself to other games," Kojima said in a lengthy interview Game Informer. "So far that has proven to be a bit difficult." What an understatement. Kojima is like that penguin in Happy Feet who ends up in a zoo with a fake arctic landscape painted on the wall and goes crazy. He's not getting out. Konami won't let him.
Kojima noted he, "would like to make more games that have that indie game taste or some completely different type of game with a big budget," before noting he'd also like to get involved with movies (presumably direct) or write a novel. Maybe the only way to stop making Metal Gear is for him to stop making games whatsoever. He actually said that he hasn't "really been close to anyone in Japanese game development," and that, "it’s easier for me to talk about my dreams with movie directors."
"I’m almost 50-years-old so I don’t have that much time left. If I were to write a list of things that I want to do before I die, it would be a very stuffed list. Because of my age I’m starting to think of the other things I have to do before I die.
"I’ve been working in the Metal Gear franchise for over 25 years. This world has allowed me to tell a lot of the things that I wanted to say. That said, it has a very specific worldview and a very specific set of game elements. I’ll probably be saying this until I die, but there are still more things I want to tell, more things I want to communicate, and more things I want to experiment with."
Hideo Kojima: The Full Interview [Game Informer]