I found the following on HB, the historical aspect is probably the closest to the truth. A shot of espresso in Italy has the same market niche as a cup of coffee from an office carafe, diner or fast food place here, with the cost running between 60 cents to a dollar, depending on the neighbourhood and town. This means the blends, in general, don't use very good coffee, and that means it's not very sweet. In the post war years through the seventies, when Italian espresso culture took shape, this was even more the case. So most blends are designed for a packet of sugar (at least); and one basically should start at that point. Oh and to add my answer, yes the customer IS always right, it is their money and it is their taste buds, I know that if I owned a business (and yes I used to) I would prefer they sent their money my way than down the street!
