After peace talks between the United States and North Vietnam stalled, communist forces invading South Vietnam occurred first.
The Viet Cong or the National Liberation Front for South Vietnam, together with the Communist North Vietnamese, captured Saigon, the South Vietnamese Capital which forced South Vietnam to surrender and brought the end of the Vietnam War.
The answer would be 'competition among consumers increases prices' because if there was a limited amount, if someone really wants that game, they'd pay more than usual when supplies sold out.
