I strongly believe that the answer to this question lies with the different cultures in every part of our world. What is considered as an acceptable standard tradition in one place, might be considered as a bad way of life in another place. Since we have different types of food in different cultures, it's only likely to see different methods used in the consumption of the said foods. As humans evolved, so did our brains and methods of doing things. China is known as a nation of inventions right from time. They always seek solutions to problems. So it's no surprise they came up with sticks, as an essential tool for cooking and staring, which eventually led to idea of chopsticks, a better means of eating than the use of bare hands. In Africa, we used bare hands till the coming of colonization which came along with the introduction of spoons. Anyways, we still use our hands till date on certain meals, i guess some cultures do not die easily.
Now, am not certain on the actual date when spoons got introduced, but am very certain that chopsticks are way older than the invention of spoons, correct me if am wrong. China is a 5000 years old empire, as well as most of it's surrounding nations. And as you know, spoons were recorded to have been in use first by the Egyptians, which the romans later adopted and introduced to the rest of the world. Hence, it is conceivable that chopsticks had been in use before the rest of the world picked up the Egyptian culture of eating with spoons which was introduced to the world by the Romans during their war campaigns.
Another thing am looking to correct in your question is the assumption that before chopsticks got invented, spoons were already an option. If you go through recorded history, you'll come to understand that China was nearly cut off from the western empires during the said period. War campaigns weren't brought to their doors by the westernerns. You will barely come across any piece of history that speaks on western conquest of china. The closest any campaign ever got to China was Alexandria the Great's battle in India where he almost lost his life in battle and later announced putting an end to his dreams of ruling the world. This simply means that China didn't get introduced to any western way of eating foods like the use of spoons as they had little or no contact with western nations during those times. They were already using chopsticks before spoons were introduced to them in a much later time, which I believe was through trade establishment with the west.