Marketing at work at its most devious.
While there are strong forces wanting you to not consume softdrinks (bad for your weight, some even claim they cause cancer), with christmas
cards it's all about making you feel guilty for NOT consuming copious amounts of them...
My parents used to send literally hundreds each year, they've now cut it down to a few dozen by scrapping everyone from their list who doesn't respond 2 years in a row with a card of their own.