My thermodynamics education is just exploding in my head...
Because they are different - not the same as you keep believing.
Different temperatures...
Different mixes of product...
Different packaging...
Different overall heat capacity...
What you think is trivial differences in temperature, actually mean a lot when you are dealing with SCIENCE and not just lay beliefs.
The customer satisfaction of the product is a blend of it's taste, it's level of carbonation, and it's temperature. It doesn't take huge swings to make a noticeable impact to the consumer. Soda fountains used to be far more fickle to dial in correctly because of these variations.