Despite raid on Pearl Harbor and the loss of Force Z, when I look at the order of battle it looks like a lot of Allied naval power was still available. USS Pennsylvania and USS Tennessee were ready for action days after Pearl Harbor, but they spent the next year patrolling off California. USS Colorado was absent from the attack entirely. The New Mexico class was rushed from the Atlantic to the Pacific...where they spent the next year patrolling off California. The North Carolina class had been commissioned months before Pearl Harbor but didn’t see action in the Pacific until post Midway. Most accounts I’ve read indicate the battleline was “training”, but these are mostly ships that have been in commission for years in a war unfolding roughly as had been anticipated for decades, so I’m curious how much more training was needed.
Famously the carriers escaped, but even they didn’t engage major elements of the Japanese fleet for the first 6 months of the war. They conducted some hit and run raids and the Doolittle raid, which is tempting to dismiss as a wasteful propaganda stunt.
The Japanese seized a huge territory in a series of stripped-down budget campaigns that were very vulnerable to disruption. Their early victories set them up to drag out a painful bloody war.
What if they had been more aggressively opposed early on? What if USS Washington and USS Lexington had been present at the Battle of the Java Sea? What if USS Yorktown, USS Idaho, HMS Warspite, and HMS Indomitable rushed a relief convoy to Singapore in January? What if the Standards were exposed to combat risk any time in early 1942?