I too drink 3-4 cups a days, which I make at home (or, much more often, at the office. Which means I save more money because I don't pay for the ingredients. At least not directly), but every now and then - say, once or twice a week - I buy a cup of coffee. Now, it's mostly a matter of convenience (I don't go out specifically to drink coffee, I buy it because I'm already out for other matters) but if I was financially struggling I could make that coffee at home (or at the office) and take it with me. But if wouldn't be that significant. If we use your numbers, that's about $2-$4/week - or about $156/year (I don't calculate the price of the jar because I already need it for the 3-4 cups I make myself, and yes I will use them up more often but at this point it's small change). Not much.

You drink 3-4 cups a day, and because you make them at home you imagine that these people who buy their coffee buy 3-4 cups a day. But is this really the pattern? I mean, I can say that I drink 3-4 cups a day and that I can say that I buy coffee, and both of these statements will be true. So maybe my pattern is the more common one? It would be enough to fill the cafes with people that only drink out once a week...