There have been a myriad of discussion about the total and final failure of KMT and its ROC in China Mainland after 1949; in the end, it can be boiled down to the fact that it widely lost the support from people of China.  But you may not imagine how badly KMT acquitted itself during its rule over Mainland as to be deserted by the people at last?  Well, attached below is a reportage that tries to tell you why from every possible aspect.  Though it is not an academic thesis, still I think it is worth your reading at:

https://user.guancha.cn/main/content?id=366802&page=1