Matthew Craw said:
Because, arguably, he bungled in the Phillipines as badly as Short did on Oahu, and with far less excuse.
Yes, he could have, theoretically, been fired. But...
1) Consider that there were no readily available replacements with his level of skill. Let's face it: yes, he bungled the defense of the Phillipines, but, when on the offensive, which the US would be on in a few months, there weren't too many better in the Pacific Theater than MacArthur.
2) Consider his level of experience. He was, in all likelihood, the only Army commander available in the Pacific to fill his position which had actually led a division+ sized force into combat.
3) Consider his experience in the Phillipines. Hell, the man was practically raised in the Phillipines. I doubt too many Filipinos would have trusted many other commanders.
4) Many in the Army considered the Phillipines a lost cause, anyhow. Although, I'm sure a more effective defense could have occured.
5) It's very demoralizing to have your commander replaced while you're in combat. Despite the fact that many soldiers in the Pacific did not like "Dugout Doug," it's not good for morale to import a fresh, comparitavely green commander.
The bottom line is that there was no one in the Pacific Theater, within the United States Army, with the qualifications, experience, and record of Douglas MacArthur.