Yamamoto was also sent out to sea for several months in 1939-1940 to remove him as a target for the young firebrands, especially in the Army, who were furious at him for advocating not going to war with the USA. When the path to war was decided he insisted upon the Pearl Harbor attack as the only way to get a temporary advantage over the US and maybe force us into a negotiated end. He had absolutely no hope of winning a long war, and by long he meant more than 6 months.
If he had sent in the third wave, he would have conquered Hawaii and had a toehold in the US. But I wonder, how long would he have held Hawaii without the Japanese military being exterminated? Or would they have launched a temporarily successful invasion of the mainland of the US?