The consequences of a failed strategy are always severe. This was no different on Luzon when it became apparent that the Japanese could not be defeated on the beaches per RAINBOW-5 and WPO-3 was placed into effect.
As for the supply situation, my understanding is that the increased number of men to feed in Bataan over what was called for in WPO-3 was known. What was unforseen were the additional 25K-35K civilian refugees and residents of Bataan that also ended up being fed out of USAFFE Quartermaster supplies.
On Dec 8, there were less than 1,300 officers and enlisted men in the USAFFE Quartermasters Corps serving the U.S. Army, Philippine Scouts and Commonwealth Army. This was about 75% understrength for what was generally regarded as the minimum number of men (4K) required to maintain efficient field supply for a force of 100K men.
Prior to Dec 1941, Brig. Gen. Charles C. Drake, the Chief Quartermaster in the Philippines issued a logistics report showing that at least 14 days under good conditions would be needed to get 180 days of supplies for 43K men into Bataan. As we know, the actual number ended up being closer to 100K soldiers and civilians.
Between Dec 8 and Dec 23, the principal quartermasters challenge was supplying dispersed forward positions under RAINBOW-5. On Dec 23, Brig. Gen. Richard J. Marshal, MacArthur's Deputy Chief of Staff notified Gen Drake that WPO-3 was in effect and that he had seven days to supply Corregidor and Bataan. At about the same time, the Philippine rail system ceased functioning.
The degraded transport system in part necessitated authorization being issued to requisition civilian vehicles. To help overcome issues of transportation and schedule, the withdrawal of supplies from forward areas into Bataan depended heavily upon the willingness of combat officers to transport their men and supplies (food, fuel and clothing), a willingness unequally shared.
When retreating forces also transported supplies, the choice of which supplies if any to transport was largely up to what happened to be available and preferences of individual officers and men.
Also, remember that some in the WPD felt that MacArthur would set the Filopino force up to be able to last even as long as 12 months.
That may have been the case but for the most part, supplies for the Commonwealth force had to come from stateside and funds were not made available by Washington in meaningful amounts until approx Sept 1941.
This is what makes abandoning items like that 10 million tons of rice all the more damning.
Contrary to popular portrayals, it's not as if these foodstuffs were sitting out there in U.S. Government depots but MacArthur somehow prevented their being used. Not acquiring millions of tons of rice from the Cabanatuan Rice Central warehouses, not transporting rice beyond the Province it was purchased in nor seizing other local foodstuffs were conscious political and humanitarian decisions by MacArthur.
Even with that, he still did not have Bataan supplied with the amount of food stuff as outlined by WPO-3. In the first week of January, quartermaster assessments of food stores on Bataan were placed at 20 to 40 days depending on the item.
Those meager stores came from field provisions rather than the reserve supplies requested by USAFFE in the summer of 1941 of which only 500K cans of C rations had arrived from Stateside by Dec 1941.
Even if we assume that this was calculated using 80 to 90k people instead of the planned 43k it still puts the built up stocks on the pennensula at less than half of what was required by WPO-3. When G-4 gave this report to MacArthur, the bleakness of the situation prompted him to issue the half-ration order on January 5th. Maybe they should have moved that rice.
Again, not moving the rice was a political and humanitarian decision.
Of course, MacArthur would have liked to have moved these supplies after he got that report, but by then he had waited until it was too late to move the amount of supplies that he would have needed to even reach the WPO-3 requirements.
And again, him being a commander in that theater for only 6 months is no excuse. He had been there longer than any of the previous commanders and was well versed on the situation from the word go.
I assume you meant his total time spent in the Philippines was longer than that of any previous commander.
He wasn't just dropped in the Philippines from a farm in Kansas, he was the man who already was in charge of training the Filopino Army, the only change was that he inherited the small American force too.
Except the Filipino regular army numbered only a few thousand and it's approx 100K reserve force existed largely on paper due to a variety of political factors in the Commonwealth and Washington.
Nobody knew the state of things on the ground better than him. But despite that he still failed miserably at supplying the men on Bataan.
In the summer of 1941 Gen. Drake submitted requisitions to the War Department for supplies sufficient to last 50,000 men 180 days. By Dec 8, 1941, only 1,000,000 gallons of gasoline and some 500K cans of C rations had arrived in Manila.
For further reading, see:
Brig Gen Charles C. Drake, "Report of Operations of Quartermaster Corps USAFFE and USFIP in the Philippine Islands, 27 Jul 41-6 May 42"
Stauffer, Aliv P., "United States Army in World War II ,The Technical Services, The Quartermaster Corps: Operations in the war against Japan",Center of Military History, United States Army, 1956
I don't think there is any proof that he did any of this for humanitarian reasons. He did short his troops on Bataan by doing that though.