US forces were on high alert and combat air patrols were up at dawn to intercept the expected Japanese attack... which never happened... until noon due to bad weather on Formosa... and when the Japanese attack finally came, the American fighters were on the ground refueling.
The gods of war just happened to favor the Japanese that morning.
Then why were all the aircraft at Clark Field not spread out, protected and ready? They were sitting ducks and the entire Air Force was wiped out in the first attack.
MacArthur could have been relieved of command and that was discussed by Roosevelt and Marshall.
Read Nigel Hamilton’s three volume history on Roosevelt as Commander in Chief.
While on Bataan, MacArthur demanded the the Philippine government pay the balance of his contract as head of the Military, some $250,000, which was paid into his account at Chase Bank and and it was reluctantly approved by Roosevelt, that gave some high level dirt to Roosevelt on MacArthur for a rainy day. File on this was found at the Roosevelt Presidential Library, by not only Hamilton but William Manchester.