Taiwan doesn't have to last a couple weeks. It has to out last the amount of time it takes the Chinese economy to crash from lack of exports or imports. Remember China is a net importer of food. No ships in their ports means millions of hungry chinamen.
Not exactly. You'd also have to remember that Taiwan's port facilities and airbases/airports will be hit hard by a ton of Chinese rockets not unlike what's been happening in Ukraine. China can also rely on Russia for imports of both food and hydrocarbons, both sides have vastly expanded land trading links in recent years. Also, China is the world's largest net food importer by value, but calorie-wise they are self sufficient, albeit barely. China exports tons of cereals and produce and imports meat. Taiwan otoh imports 70% of their calories, shutting down their trade puts them on a strict time limit to win the war or be forced to surrender. I'm not sure how much food Taiwan has in storage, but cutting off Taiwan from international trade by force is a much easier task than a full scale invasion.
And people think MacArthur was bad.
People give MacArthur shit for quite a few things, but most of his "blunders" were either inconsequential or correct/justifiable at the time.
Him changing the defense of the Philippines at the last second makes sense when you consider that the first thing he heard was that the bulk of the US battle line was destroyed at Pearl Harbor, and that the naval base suffered significant damage. The original War Plan Orange specified a withdraw to the Bataan peninsula, where they could hold out for about a year at most. This makes sense if you are operating under the assumption that an allied fleet will be steaming across the Pacific ready to save you, but it was obvious from day 1 that the islands were doomed and the US Pacific Fleet would be a long ways away from challenging the IJN so far westwards. With that in mind, a defense on the beaches, while far riskier, makes much more sense. The only way to hold the Philippines long term was to destroy the Japanese armies in the field, not by hunkering down and giving up all the ports.
People love to shit on him for appointing George Kenny to run the air war in the Asia-Pacific instead of Doolittle. People pin this decision solely on MacArthur's ego, but overlook Kenny's accomplishments. Kenny, unlike Doolittle, had actual combat experience from WW1, and served as an attache to France during the German invasion of 1940. He had seen modern air warfare and seen what to do and what not to do. He didn't want overly ambitious officers who may or may not have had a clue what they were doing, he needed guys who he could count on
now, with active combat in the air in the South Pacific, not guys who could "figure it out" by late 1942. Kenny also proved an incredibly rescorceful officer, when the USAAC refused to provide drop tanks thanks to the Bomber Mafia, Kenny contracted Ford of Australia to make drop tanks all on their own. This resulted in P-40s, P-39s, and later on P-47s and P-38s to achieve air superiority over New Guinea long before the USAAF relented and finally approved drop tanks for their fighters in November 1943.
His invasion to take the Philippines instead of Formosa was also established out of real world concerns and not an ego trip. Both would cut the Japanese Empire in two on the seas, except Formosa was much more highly defended, way more fortified, was within range of IJA and IJN land-based air assets out of China, and was home to a population that was loyal to Japan, including a significant Japanese population outright. The Philippines had none of this, and had a population that was eager to support their American liberators. If anything, avoiding Formosa prevented potentially an Okinawa on a far larger scale, where far more US troops died taking fortresses dug into mountains and large parts of the civilian population either fought alongside the defenders or committed suicide to avoid capture.
As for Korea, starting WW3 in 1951 was maybe the last chance to defeat communism forever without risking nuclear destruction upon America and Western Europe. If Stalin backed down, an expanded war against China was unwinnable for Mao and company, as most of their veteran troops all died in the Korean campaign without a huge surge of US troops. The only thing I'd harshly rebuke MacArthur over was not encouraging Hirohito's conversion to Christianity when the Emperor offered it to him.