People seem to just brush over the fact that the
KMT lost because the Maoists were simply more
compatent than them in every way and the KMT never showed any hint of being able to control a unified state from a single capital.
China under the KMT would be as messed up as the Congo is today. People grossly underestimate the Maoist role in actually unifying China under a single government, instead of the KMT’s unstable pack of periodically feuding warlords. Most of whom would kill or be killed before giving up their private fiefdoms, or worse try to usurp Chiang. Not to mention te crazy levels of incompetence and corruption in the areas the KMT actually ‘’governed’’. To the degree that crime cartel bosses were members of Chaing's inner circle.
Anyone who looks at just how cruel, incompetent, stupid, sort-sighted and riddled by infighting the KMT was could never make the claim that China under it’s rule would prosper. There are very good reasonS they lost the civil war. Despite having control of the vast majority China’s land mass & population, having a 5 to 1 numbers advantage and being lavishly supplied with US money and weaponry. It’s simple the Maoists were simply better in every category (aside from weaponry) and weren’t as wretchedly unpopular as the KMT. Whose troops were mostly press-ganged peasants with no morale at all and whose ''generals'' were of dubious loyalty and stockpiled arms for use against old rivals.
The KMT’s ‘’success’’ in Taiwan could never be replicated on the mainland, on a large-scale. Taiwan in 1948 had an urbanized & easily controlled population, had a good infrastructure and industrial base built by the Japanese and had US aid poured into it by the billions. Even the KMT couldn’t screw that up. Also the shock of defeat & exile did cause Chiang to clean up his act and it also eliminated most of Chiang’s old/potential rivals.
Assuming the KMT ITTL has amazing luck and the whole Maoist leadership drop dead (so no Mao, Zhou or Deng etc) and the Communist fall into disorder, you now had a deeply unpopular, corrupt, incompetent and unstable regime. Suffering factional infighting and facing constant rebellions and mass desertion in it’s armies
To top all that off there may or may not have hostile Red Army troops in Manchuria to enforce Soviet intrests depending on the KMT's stance during the Cold War.