The problem with the tank is that other systems delivering the same death potential (RPV’s and bombers) have a significantly lower logistics cost. It is difficult and slow to get the tank to where you need it and the cost of keeping it fightable (fuel and maintenance) is exorbitant. Many of the places where you would use the tank are not suitable for maneuver, so the tanks get bogged down or restricted to a few easily attacked routes. The Army would like to forgo the high fixed cost and low utility of the tank for more modern methods.
Relying on airpower works if we only bomb third world countries but that approach is dead in the water if we fight someone like Russia or China that actually has a modern air force and air defense systems.