One of the main reasons is that their identity can't be recognized by later Orthodox countries, because in the final analysis, they are ethnic minorities. In those orthodox countries with the Han nationality as the main body, they are always barbarians and uncivilized, so they do not recognize the glorious history of these ethnic minorities. Therefore, when they revise history, they will not make a very formal and positive record of these ethnic minorities. But that doesn't mean we can ignore the glorious history of the dog army and not record it.
Dog Rong clan has appeared since our Zhou Dynasty. At that time, some ethnic minorities gathered in western China. However, because they were nomadic people and had no fixed production resources, they began to find ways to March into the Western Zhou Dynasty, which was adjacent to them at that time, and seized the land of ordinary people and some cattle and sheep as their living resources. Therefore, in order to solve the contradiction with the dog Rong family, the Zhou Dynasty was always very upset. Sometimes I fight with them, and sometimes I negotiate with them intermittently.
In the end, Jiang Ziya solved this problem properly, that is, using money, beautiful women, cattle and sheep, and a fixed site to arrange the dog Rong clan, which is today's Ningxia area in Gansu. Jiang Ziya arranged for the dog family to live in this area, so they were very honest. In return, Jiang Ziya also asked the dog family to provide them with chariots, so we can know that the chariots were not developed by the Zhou Dynasty itself, but by the dog family.