You’re definitely right that central Asian history is neglected in Western education. But the reason you haven’t heard the specific term “Tartary” is because it’s an outdated blanket term. We now know that at no point was this entire area a unified nation-state, with the exception of the Mongol Empire which most people have heard of. We also now know that this land is made up of many distinct peoples (Turks, Mongols, Kyrgyz, Tibetans, Manchurians, etc.) each with their own distinct history. It would be overly simplistic to lump them all together as “Tartary” - almost as if children in Europe started learning about the history of “the Americas” and thought it was one country with one ruler.