The answer to this is very clear. Beliefs can change, even within the same generation and within the same person.
Think of how religion works. Often times, within a generation, people lose their beliefs. What parents belief is not often carried over into what children belief. The same goes for almost any topic - politics, music, worldview.
The reason for this change is mainly due to the changing world in which we live. Through globalization, we come into contact with people from around the world. This fact alone challenges worldviews and in time what was once familiar becomes less so.
So, beliefs can and do change. With this said though, it is also possible to keep the beliefs of a past generation, but it will take some work.