Tank Obsolescence

 Tanks can't see and need an infantry screen. Tanks without infantry just get shot from the side by ambushing RPGs.

 If tanks do have an infantry screen, then get a bunch of snipers. Shoot the infantry screen from a couple miles away. Then the tanks don't have an infantry screen, so you ambush them with RPGs and destroy billions worth of equipment using millions worth of munitions. You can also clear the screen with some laser pointers and an artillery barrage. 

 This means both the armour and the engines on tanks are pointless. They can't travel any faster than a man on foot. They can't survive anything that can kill a man on foot. 

 Worse, drones now exist. Wire-guided drones are immune to both jamming and triangulation, and it means your RPG ambush doesn't have to have LOS on the tank. The armour column needs something a lot stronger than an infantry screen to stay viable.
 Even if the infantry screen takes cover and the snipers can't take them all out, at worst the tanks are now stationary. Sitting ducks. Easy marks not only for drones, but RPGs and heavy artillery.

 The large guns are useful. E.g. if you figure out where the snipers are sniping from, you'll find the tank gun sees their cover as invalid. The armour and any kind of high-performance engine are worse than useless.