>>33062825He didn't leave. Basically
Red/Green - Gold/Silver (Director/Scenario/Game Design)
Crystal - Emerald (Executive Director)
Diamond/Pearl - current (Executive Producer)
And all side games credit him with the "original work" which is just a roundabout way of saying that he didn't work on the game, but it's based on a series of games he came up with.
Executive Producer is basically the credit given to a higher up who doesn't actually do anything on the project itself, but has given the go-ahead to work on it. Yamauchi, Iwata, and Kimishima have all been considered "Executive Producer" for every Nintendo-made game in their respective times as President of Nintendo.
