Kojima himself told Xbox Wire that at some point somebody else will be in charge of making new entries in the popular stealth franchise, Metal Gear Solid.
“The only thing I can say for certain,” Kojima mused, “is that I personally will not be able to carry MGS forward for another 25 years. However, with new talent at the helm guiding the series through each new stage, I can easily imagine a world 25 years from now where a new MGS franchise continues onward into the future.”
Kojima is currently 50 years old. Given he’s said before that he’s done with Metal Gear and that clearly turned out to be not true, it’s conceivable that he could live to be 75 while continuing to produce these things.