Japan was doomed by the decision to go to war against the United States.
Japan was pushed into it by the US. By that time oil was critical for conducting a sustained campaign, and we had orchestrated an embargo in July that cut them off from 88% of their oil supplies. Roosevelt had the US in the war already, if not officially - between the embargoes in the east and US destroyer attacks on German submarines our full participation was inevitable. That being the case, Japan felt it would be better to strike first. I probably would have done the same.
While clearly unable to hold off the full might of the US economy as it was brought to bear, the Japanese government felt it might be able to convince the US people actually carrying on an all-out campaign at the same time we were at war with Germany would be too expensive, and a settlement could be negotiated. Germany was supposed to be their ace in the hole, soaking up enough war materials to enable Japan to survive.
World War II broke a pattern that had held for a century. Wars weren't fought to the death - you fought until the winner was clear and then you negotiated a peace. I suspect the people in power believed the worst case would involve surrendering Manchuria and French Indochina, something they would have to do anyway as a result of the oil embargo.