Tech has won something like 18 out of the last 19 games. Since UVA is already bowl eligible, they don't have that as an incentive like Tech. They do play for something called the "Commonwealth Cup", symbol of football supremacy in the Old Dominion, I guess. If they win, then Tech would be 5-6, thus the game against MU gives them a shot for 6 Ws, and to keep their consecutive years (around 25) of bowl game participation intact. Without Tech having a shot for 6 wins, the game against MU will NOT take place.