You may or may not be surprised to know that there was no small number of high-ranking Japanese officers who were telling Yamamoto this very same thing when he first brought up the idea in January 1941.
You would probably be surprised to learn how many American military officers and members of Congress dismissed concerns about the vulnerability of Pearl Harbor for the same reason.
I don’t doubt it. I think Yamamoto was under duress to make the decision, and wrote disparagingly about it. But he did as he was ordered. The army leaders were calling the shots. I read (somewhere, can’t find a peep about it right now) that a military plan to assassinate him was narrowly averted by a promotion. Oh, there is almost a reference to this on the wiki-wacky page. The assassination worry was in 1939, IOW a couple years before Pearl Harbor.
Glad our fliers killed his ass when they did. I don’t think it had much of an impact on the outcome, because the Japanese high command understood that they didn’t have sufficient fuel available to keep their fleet in action as much as necessary, thanks to our fighting men.
If the Midway plan had gone according to, Pearl Harbor would have been in range and would have become useless to the USN. Would have been a lot harder war, and longer, because we needed to get close enough for the Enola Gay and the Bochscar to hit their targets.
It is my understanding that Yamamoto told the Imperial Staff that attacking the United States would be a disastrous blunder because he had studied and traveled throughout the US as a junior naval officer and saw what we were capable of industrially. But they told him to plan for attack anyway and he dutifully did so.