Because there was literally no way for them to do that, logistically, and if they had wanted to they would have had to first subdue Wake, Midway, and the main Hawaiian Islands chain itself or face attacks all along an enormously long supply route they would have to maintain to launch and invasion. (They would likely not have been able to sustain an invasion of Midway in the long term, which is significantly closer to Japan; the entire point of that operation was to attempt to draw out the Pacific Fleet into a decisive battle and destroy it.)

Japan had no intention at any point of invading the U.S. mainland; their war aims were to seize the colonial resources of southeast Asia, build a defensive perimeter in the Pacific, and force the US fleet to come to battle. They envisioned that battle being one where the Americans were attritted by submarines, airpower, night attacks, etc. across the Pacific and finally destroyed in detail near the Japanese home islands, after which the U.S. would sue for peace. (If that sounds improbable, keep in mind that this is essentially how Japan won the Russo-Japanese war.)