its important to note that the Fleet Problems (of which this was one, and there were many) also simulated sneak and non-sneak attacks against the Panama Canal, and there were multiple simulated attacks against Pearl Harbor. There were also tests of carriers acting alone, carriers acting as scouting forces, carriers acting as the head of a strike force. For anyone interested in this - I highly recommend "All the Factors of Victory" about Admiral Reeves. During this time period there was a deliberate and systematic effort to develop carrier aviation and tactics. Far from being some rogue effort that was suppressed for political reasons, it transformed the navy and put in place the foundations for eventually winning the war - even with a rough start. The Essex carriers (for example) where specified and laid down according to what the USA had learned from the fleet problems.

Why the rough start? I would point at Admiral Kimmel. Kimmel's predecessors (Reeves and Richardson) understood that American Bases (Subic Bay, Panama Canal San Diego, Pearl Harbor - in that order) were at risk from a Japanese surprise attack. Reeves was obsessed by it - which is partially why this Fleet Problem occurred. When Reeves retired, Richardson took his place. While story goes that Richardson was fired for making the point that Pearl was vulnerable, that doesn't appear to be the whole story. Richardson's main complaint was not sneak attack, but rather that Pearl Harbor didn't have the facilities to adequately service and train the fleet, and his solders would be bored during peacetime. Regardless, he was also concerned about a sneak attack against American assets.

Richardson was insubordinate - at one time questioning the role of congress and the president in dictating military policy - FDR fired him, and replaced him with Kimmel.

Kimmel on the other hand was obsessed with the Japanese population of Hawaii, particularly the risk of sabotage. Rather then focus on radar, or keeping the Fleet at Lahaina roads - where they could move freely in case of a sneak attack - he kept the fleet bottled up (save the aircraft carriers) and the planes lined up in roads.

Even then - the USA had put in place things like Radar and built up Pearl Harbor rapid ally enough that they could have responded if everything was perfect. But you had one force that had been at war for 8 years before the USA entered, and the other at peace time. The focus on sabotage instead of fleet defense doomed them.

While the Niihau incident occurred, it was obviously a far smaller problem the the Fleet burning in Honolulu.

Finally it needs to be noted that a ton of people expected a surprise attack. They just expected it against the forward US base (the Philippines) or Singapore

Ironically, the one area task force wise that that the Japanese were inspired by the USA was based on not by Fleet Problems, but instead propaganda. The story goes that the Japanese commander in charge of Planning - Minoru Genda - was watching American news reels, which showed American carriers acting in formation, in the same frame of film. While this was done for filming, Genda applied it to actual battle formations. That gave Japan enough firepower to target the entire Pacific Island, not just a single ship or even a single base.

The Japanese were also far more inspired by the attack on Taranto by a set of obsolete biplanes that basically wiped out Italian sea power (not that there was a ton of that) in Europe.