One reason is age. The closer you get, the less obvious the shaking is. This is because at that time, film or film technology was basically immature, especially some established film companies, such as Shaw Brothers and Jiahe in China, are still shaking badly and the picture quality is relatively low. You see, there is basically no problem with the newly made movie LOGO recently.
Another reason is that editing deliberately matches the plot of the film, making the title shake or other artistic expressions.