The 1989 Tiananmen Square protests did accomplish something. It showed the world that people were tired of the regime in China and had growing levels of anger about the government. And although the protesters were punished, they still got their point across to other countries that everyone was not happy in China.
The 1989 Tiananmen Square protests established a road for massive changes both in China and in media. The government of China had to stand up to the idea that became embolded with these protests - the idea of stopping government policies which the infamous "Tank Man" picture so eloquently summarizes. The result, the so-called "two door" policy, led to an economic shift in China's development whereby the government of China sought to placate the younger student masses with the ability to gain massive economic rewards - albeit the second door of politics being strictly closed off.
The 1989 Tiananmen Square protests did not change much of China's policies, but it had many consequences especially from foreign countries who reacted to China's actions by reducing foreign aid, reducing trade opportunities and a reduction of tourism. Some of China's Leaders were also replaced do to their lack of support for military action against the protesters.
Yes, the 1989 Tiananmen Square protests accomplished a great deal, in that they brought the issue of Chinese human rights to the forefront of the discussion of current events. The protests made China famous. China then received a great deal of pressure from the rest of the world to make their nation more free, a struggle that continues to this day.
I do not think the 1989 Tianamen Square protests didn't accomplish anything. As sad as that sounds, the protests are only something that people outside China like to use as a psuedo symbol of the power of protest. Unfortunately, it didn't really do anything since China act more like a country of dictatorship.