The issue is that the KMT lost a lot of popular legitimacy during the War. A continued Chinese Civil War, whilst possible, likely devolves into a massive Vietnam if the USA intervenes in favor of the KMT. If they don't, a few minor PODs can probably prolong the war another couple years to no substantial change. However, if the USA intervenes, the combination of economic fallout from the war, political division, and increased dependence of the CCP on Moscow mean that the Sino Soviet Split is quite possibly butterflied.