A lot of people think there was total incompetence in the Philippines.
True and that's because the Philippines lay in the path of the Japanese southward drive for raw materials in SE Asia and Indonesia.
The fact that our planes were destroyed on the ground at Clark field a day later always struck me as criminal.
You have to be careful here and go back to original sources. If I remember correctly, MacArthur was notified of the attack on Pearl Harbor but had not yet received orders to commence offensive action. Therefore, he didn't have the freedom to order a B-17 strike against Formosa.
The radar crew at Clark were inexperienced and the set may not have been properly working either. A network of ground based Filipino aircraft spotters were also used but for whatever reason, failed to sound the alarm in time.
MacArthur ordered the fighters up, but the timing was off and most were on the ground refueling when the Japanese bombers appeared over Clark.