This is a good case for lazy and bad parenting.
I know alot of kids that refuse to drink water.
I started my son on water when he was very young and he drinks water 99% of the time. This doesnt mean he won't drink soda but he perfer water and drink tons of it daily.
It all about how you parent and what you instill in your children.

It’s fast, cheap, and kids eat it.. It relies on the human craving for sugar & fat/ grease ..who’s calories once gave us the energy to hunt, run, and stay warm. Our life expectancy was probably one teenth what it is now, and lacking necessary activity our bodies store the excess calories - but this is America, the USA - whatever makes a profit wins!

If anyone ever asks me what the hardest part of parenting was, it was teaching, or practically forcing my children to eat properly.. Crying fits ..and likely resentment to this day - but, like me, they’ll eat about anything, they don’t waste food, they eat to live - not live to eat, they seek a balanced diet, and they’re not fat. Not easy

It's quick and easy to pick up at the drive thru, has a good price point although not good food value, plus it is well marketed.