Apparently the ice cream vendor ran out of dishes and started substituting rolled up wafers from another vendor. The soda jerks as they were called then, had to come up with another concoction. So, they left out the soda, added a thick syrup over the ice cream and changed the spelling to Sundae. During the Prohibition, ice cream became even more popular and lots of new products were introduced. Today we have a huge range of frozen dairy and even non-dairy items such as sherbets, sorbets and ices.
People can choose premium, low fat, even no fat ice creams and yogurt.
Ice cream comes from milk or cream based mixtures. Ices come from those without dairy products such as juices and fruits. The most important step is the freezing. You need to stop the formation of ice blocks by stirring the mixture while it's freezing. The more stirring, the slower the freezing, the tinier the crystals, the smoother the ice cream.