1. I quantified the amount for lunch because people don't think about the cost of eating out. If all someone does is eat out every day for lunch at work, it is a small expense compared to taking your entire family out several times a week (one person versus the entire family each time)...unless of course you are paying credit card debt and trying to get out of it. Buying ANYTHING comes with a HUGE additional carrying cost.
2. You ignore the time value of money. Also, you used a 40 year average of about $6 a meal. Too low. Between the two items, the impact would be much larger, but then again, this wasn't about lunch (see #1).