If the enzyme renin is only in children, then why the production of milk in beverages?

Question

Want to know the essence of milk in beverages as no enzyme to digest

Answer 1

milk should not be consumed after child years. The Dairy Associations only tell you to drink it for their profit only. Oh, the government gets a cut of the profits, too.

Humans are the only animals that consume milk long after childhood.

The nutrients found in milk can be attained by eating certain vegetables like broccoli.

Answer 2

Some other enzymes can also (if only partly) break down the casein in milk. It also contains lactose and fat and that is important as an energy source (especially for the "developing world" where food is often not plentiful).
Either way it tastes good.