Why are some folk customs related to traditional festivals gradually forgotten, and only diet has survived?

In the past, traditional festivals not only referred to this day, but also had more ritual activities and awareness for this festival. In modern society, the purpose of the past has been weakened, and festivals are more a formal habit. For people, there is no direct connection with production and life. If there is a certain conflict between life and life, this formal habit can easily be broken. But people still need a ceremonial transition in their hearts, so people still need the form of festivals. However, how to give this form operability without particularly affecting production and life, then it is highly likely to be placed on food, because food itself is a necessity for people's survival, and different foods also reflect the characteristics of different seasons and festivals, which can become a * * * link between traditional festivals and modern life, so food can be preserved as a manifestation of festivals.