Why didn't Zhuge Liang promote the research and development of weapons, and only used weapons or tools such as crossbows, mines and wooden cows and horses as a last resort?

First of all, even crossbows, wooden oxen, flowing horses, and eight arrays of the art of war are all found in the official history, and even the enemy countries and future generations can't help praising them. The upstairs people haven't seen the official history, so don't talk nonsense simply by relying on a product of the Three Kingdoms ~ Secondly, Zhuge Liang didn't know these things in the early days, but groped them out in the constant struggle against the enemy. Just because he is an inventor doesn't mean that he knew how to make these instruments from birth. Moreover, the method of making Muniu Liuma is clearly recorded in writing. It is divided into several parts, each of which is several feet and inches long, and how to connect and operate it is clearly recorded. Now it can't be recovered. It doesn't mean that Zhuge Liang didn't stay, and it doesn't mean that he was afraid to open the so-called "Pandora's Box". Finally, these things were not used as a last resort. We saw that in the fourth Northern Expedition, Zhang Jaw was shot with a crossbow, while in the fourth and fifth Northern Expeditions, the Shu army also used wooden cattle and flowing horses as tools for transporting grain. Obviously, Zhuge Liang could not make these things by himself, so naturally there was a special manufacturing department. The bronze crossbow machine of Shu unearthed in later generations also clearly has the names of the production department and production officials. The crossbow is not Zhuge Liang's creation, but from the initial ordinary crossbow to the crossbow machine that can shoot ten arrows with one crossbow, it is his painstaking efforts, and Zhuge Liang has been committed to strengthening the power of weapons. From wooden cattle to flowing horses, he has been trying to make the tools for transporting grain more convenient. How can he say that he has not improved his weapons?