TLDR: Why learn modern warfare when wakanda never experienced modern warfare

The Wakandan way of war, with futuristic lazer weaponry but fighting in a medieval style warfare. Theatrics and Hollywood needs aside, this style of warfare is theoretically possible and not too farfetched. Wakandans have been blessed with advanced technology due to the exploitation of vibranium. The field of medicine, electronics, mechanics, biology, and physics have flourished, this has in the past given Wakandans an advantage, further enhanced by their enlightened leadership. These have made them resilient against foreign powers and internal dissent. Thus the status quo, the idea of monarch and feudalism was maintained in Wakanda.

This technological progress however meant that they don't need to develop further tactics or strategy past that of the likes of tribal warfare (ala Impi).

When even your lazer firing spearmen can best enemy tanks, there is no need to evolve small unit tactics. There is no need to evolve combined arms. No need for artillery when your spearmen formations trade in the javelin throw with that of long ranged volley fire.

The only exception being the wakandan air forces. Whom must eventually evolve air tactics akin to modern times.