Why did the protests at Tiananmen Square not bring the same change to China that occurred in Eastern Europe?

It was due to the vaccine effect of the Great Cultural Revolution. The Great Cultural Revolution was a movement of democracy that evolved into mob rules. Ten years of mob rule is much stronger than all the color revolutions added together, including the incident of Tiananmen Square.

The protests at Tiananmen Square were ignited by the death of the former General Secretary of CCP, Hu Yaobang, who was famous for his correction of the Great Cultural Revolution. The most important lesson the Chinese learned from mob rule is that a country needs the rule of law. Color revolutions, including the protest of Tiananmen Square, were to deny the authority of the government so as to deviate from the rule of law. The protest did not seek a solution within the system and did not obey the rules.

No Chinese would like to repeat the mob rule that happened during the Great Culture Revolution. In fact, thanks to Hu Yaobang, Chinese people had sympathy with the CCP carders for their suffering during the Great Cultural Revolution under mob rule.

People of Eastern Europe had no sympathy for CCP carders who had had too many privileges all the time.

The Great Cultural Revolution is when the CCP mobilized Chinese people to a color revolution against CCP itself and lasted for ten years. Compared with the mobilizing of Chinese people against the CCP for ten years in the Great Cultural Revolution, two months at Tiananmen Square is a small potato. If CCP can survive the Great Cultural Revolution and launched a satellite during the Great Cultural Revolution, it definitely can survive any color revolution.