And on Sundays, even if you would rather eat at Chic-fil-a, you spend your money elsewhere (assuming you aren't fasting). Seriously, this isn't rocket science.
Frankly, I'm sure the owners of these establishments would heartily agree with me. The fact that they lose money by closing on Sundays shows how important their religious principles are to them.
Well, you will find that many restaurant owners don't actually do the work. Most just stop in to make sure their investment is doing well.
Ask the employees if they appreciate the Sunday off. I honestly think it's great that a company values guaranteeing 1 weekend day for the employees to be with their family above making a few extra bucks on the slowest business day for most quick-serves. Glad the owners principals are in the right place.
Also consider that the sheer decreased level of turnover by giving every employee a weekend day. Putting it simple, restaurant workers don't get weekends. The might get a monday and thursday off, if they are lucky, they get two week days off in a row. Labor is by far the most expensive variable cost a restaurant deals with, and turnover is the biggest problem of labor cost in the industry. Speaking about the company I work for personally, the ungodly amount of tax burden we take in for our turnover costs us many millions of dollars each year. Closing on Sunday might not be as losing of an idea as you may think.