Why do Hong Kong use traditional Chinese characters? Because Hong Kong was ceded to Britain as a colony by the Qing government in the late Qing Dynasty, Hong Kong basically did not belong to China at that time. Even after World War II, with the rapid development of economy and society, Hong Kong was still under British colonial rule, and the traditional Chinese characters of the Republic of China were always used. It was not until 1997 that Hong Kong began to return to the embrace of the Mainland and established the Hong Kong Special Administrative Region. Although it has complete sovereignty over Hong Kong, Hong Kong still maintains its original capitalist system, the so-called "one country, two systems".
Why does Taiwan Province Province use traditional Chinese characters Taiwan Province Province? It was also in the late Qing Dynasty that the Qing government ceded it to Japan as a colony. However, after World War II, the defeated Japanese were forced to give up their occupied land, and Taiwan Province Province returned to China. However, after the defeat of the national army, they chose to return to Taiwan Province Province for development. Since then, Taiwan Province Province has been in a state of great division from the motherland, and up to now, the two sides of the Taiwan Strait have not been reunified. When the national army returned to Taiwan Province Province for development, China always used traditional Chinese characters, so of course, Taiwan Province Province always used traditional Chinese characters. By the time simplified characters are implemented in mainland China, Taiwan Province Province and mainland China have been isolated from each other, so Taiwan Province Province will naturally not use simplified characters with mainland China.
At the beginning, Hongkong was considered as a relatively developed place in China, and people's education level was relatively high. Because the traditional Chinese characters are always used there, and the whole place in Hong Kong is not big, it is relatively easy to popularize, and so is Taiwan Province Province. The population and land of these two places can't be compared with the huge mainland.
Why did China change traditional Chinese characters into simplified ones? China's use of simplified Chinese characters has a great relationship with the social environment at that time, because in the 1950s, China was in a state where everything was in ruins. In order to improve the cultural level of the whole people, the state has set up literacy classes. But because traditional Chinese characters are more complicated, it takes a lot of time to learn. The students in literacy classes are basically adults, and they don't have much time to study at all, which leads to the fact that simplified characters are based on everyone's needs.
After all, there are still many places in China where people have no chance to study and there are many illiterate people. Especially many people who live in mountainous areas, most of them have never left their hometown. Compared with simplified Chinese characters, traditional Chinese characters are much more difficult to learn and have higher requirements for learners, which deepens the difficulty of learning culture. In order to enable most people in China to read and write, simplified characters have been popularized nationwide. Perhaps because simplified characters are easy to learn and widely used in life, they have been used until today.