It was FAR beyond the logistical capabilities of the IJN to support and much larger than the IJA was willing to devote forces to.

The immediate goal was to allow for the relatively unopposed taking of the Southern Resource Area, then turn to defeating the USN. Even without a first strike it would take time to organize the fleet and prewar plans called for the Pacific Fleet to remain essentially on the defense to begin with, giving Japan to secure what she really wanted and needed. For decades the plan had been to force the USN to fight through chains of barrier islands until they would be weakened and far from home and the IJN could fight one large "Pacific Jutland" battle of decision int he spirit of Mahan.

But by trying to capture Hawaii Japan would reverse the roles, now it would be the IJN having to fight far from friendly ports and home, while the USN could lick it wounds on the West Coast. And the Sea lanes to Australia keeping them supplied and in the war would still be open.

Even securing a regiment in the Spring of 1941 to occupy Midway was a gargantuan task to et the army to agree to. And a sizable number of officers in the fleet thought it was beyond the ability of the IJN to keep supplied once there, and were skeptical of the plan to seize an island so far forward, though still not as far as Hawaii.

Because that was not part of their immediate plan. The attack on Pearl Harbor was to annihilate the US Pacific fleet - ships and military personnel. Remember, Hawaii is an extremely isolated archipelago, the furthest away from any mainland east or west of it.