Why did the Roman calendar include, and the government pay for so many religious festivals?

Festivals were also held in ancient Rome in response to particular events, or for a particular purpose such as to propitiate or show gratitude toward the gods. The rituals consisted of festivals, offerings (often of food or wine), and animal sacrifices. These rituals had to be carried out regularly and correctly in order to retain the favor of the gods towards the state, household, or individual.

Explanation:

one of the negative side effects were the economic losses the events of september 11th caused. many, many people lost their jobs as a result of a downturn in the economy after the terrorist attacks.