Does the Philippines remain in Allied hands in this timeline, and what happens to MacArthur?
Short answerThe Philippines still falls; MacArthur may retain a ground command, but the viable defensive line is farther south around Singapore, Sumatra, and Java.
NotesThe fleet cannot place enough ships and ground strength into the Philippines to prevent its fall. Borneo and Celebes also probably fall initially, though submarine pressure makes Japanese control and resource extraction tenuous. Air bases across Singapore, Sumatra, Java, and Australia could support a more defensible southern line and keep Japanese forces farther from Australia. MacArthur's later role then depends on how he works within a functioning ABDA command rather than on saving the Philippines.