Answer:
A generalization that can be made is that life is full of challenges and that eventually some of them will not be overcome, it is not possible to avoid, just accept.
Explanation:
The text shown in the question above shows how often wise, powerful and intelligent men like Gandalf and Elrond create very good and effective plans to overcome the challenges that arise during life. However, even good and efficient plans can be frustrated and fail to overcome challenges. This is because life is unpredictable and full of surprises and it is normal for our plans to fail sometimes, because that is how reality works. In short, the text states that we will not always be able to escape defeats, because they exist and we cannot avoid them.