someone with knowledge of military tech (harm, glass, etc) explain to me why we don't just make remotely piloted drones to blow up tanks instead of making tanks to blow up tanks? it sounds a lot easier and with 0 risk of human loss.
Short version: Well its like a game of rock paper scissors and always trying to out do the other guy and it wouldn't be too practical in large conflict against because they will make something to counter the drone.
Long version with more details and history:
Originally tanks weren't meant to fight other tanks, they were meant to breach or bypass defenses such as bunkers and trenches and then take land. Some countries see them as offensive weapons while others saw them as support weapons. Most of the original tanks from WW1 and the interwar war period only had machine guns or small cannons. Many experts thought they would render infantry useless and be the dominant weapon on the battlefield.
So the Spanish civil war and each side had tanks imported from Germany, Italy, or the USSR. Because each side was trying to take land, these tanks kept running into each other. So countries observing the conflict knew that in future conflicts tanks would be running into other tanks and began drawing up ways to gain the other hand on the other. The soviets produced the T-26 which had a 37mm gun that could penetrate almost anything. The German Panzer I and Italian CV-35 tanks only had machine guns and were easily outmatched by the T-26. The Germans had the Panzer II which had a 20mm auto cannon(basically a cannon that shoots like a machine gun) which could take out T-26 but it would be adequate enough. So with lessons learned from the Spanish Civil War they designed the Panzer III, Panzer IV and the USSR went on design several tanks such as the T-35, T-34, KV-1.
Germany and the USSR knew that they would be fighting against each other one day and they knew that the tank would be a big part of future conflicts. The Germans decided that they would make tanks that could go fast and operate alone with enough fire power to cause damage. The Soviets experimented more with different variants by introducing weight classes such as light tanks which were meant to scout, move fast, and operate as an independent group. They made medium all rounders, and heavy slow hitters. Some countries tried making land battleships that had many turrets, but in the end only one turret was all that was needed. When WW2 began the British and French had let their tank fleets become outdated and obsolete because they didn't pay attention to the lessons from the Spanish Civil war and ignored the improvements that the Germans and Soviets were making. Eventually everyone hoped on the arms race and began trying to out do the other guys tanks. The armor got harder and thicker, guns got larger, they became faster and more fuel efficient and could move farther.
However that wasn't all countries did. Countries experimented with cheaper alternatives to combat and counter these tanks. So anti-tank rifles and heavy machine guns were made that fired large projectiles such as the .50 caliber bullet and 20mm shell were made to defeat armor, but these became obsolete as tank armor became thicker. They made towed guns that fired armor piercing projectiles and could be pulled by soldiers, horses, and vehicles, but these became obsolete in the 1950s. The Fins figured a bottle of burning gasoline would suffice and actually worked against soviet tanks hence the Molotov roostertail, however most modern tanks are protected against molotovs. Anti-Tank grenades were also made, but they were to heavy and had limited range entry. Tank destroyers were invented to use speed and fire power to counter tanks at the expense of protection, the earliest ones started out as trucks with a large gun and eventually evolved into jeeps and armored vehicles with bigger guns which in turn became jeeps and armored vehicles with a guided missile launcher.
Most of the early armor piercing rounds were just solid kinetic penetrators and to counter those, they just make tanks thicker armor. The Russians learned that if you slope the armor and the hull you produce an effect that makes the armor thicker. It was discovered that a chemical warhead could easily penetrate thicker armor and do more damage with a shape charge through the Monroe effect. These chemical warheads used a copper liner that would melt and be sprayed into the armor as a solid projectile. So weapons like the Bazooka, Panzershrek, Panzerfaust, PIAT, and HEAT shell were made. However HEAT was expensive and became ineffective as tanks were being made with thicker rolled homogenous steel. So HEAT was mostly reserved for missiles and to be used against lightly armored vehicles while solid projectiles were to be used at longer range and against tanks. The solid penetrator eventually evolved into an armor piercing dart made of tungsten or depleted uranium. However in recent times HEAT has lost its effectiveness against a new type of armor which combines ceramics, RHA, and DU as reactive armor which can be replaced and be bolted onto a tank's hull. So they just keep making heat projectiles with larger warheads and stronger armor piercing darts.
Weapons like the bazooka were to heavy and required a team of two to operate, to simplify this. Weapons like the M72 LAW were made so that every soldier could carry two disposable launchers. Heavier weapons like the recoilless rifle were made to compliment the LAWs, but they were unguided and had limited use. So manually guided missiles were invented. Some of these optically guided missiles could be carried by a team of soldiers like the M47 Dragon, while others like the TOW required a tri-pod or had to be mounted on a vehicle. However these missiles required that the user guide the missile to the target and left the user vulnerable. So weapons like the Javelin were made so that soldiers could target and launch the missile without having to guide it, these missiles also attack the most vulnerable part of take which is the top where the armor is the thinnest.
In addition to that, helicopter gunships were invented to carry guided missiles and auto cannons to counter moving mechanized forces. Planes were also made to attack tanks with guided anti-tank missiles and cluster bombs which scatter hundreds of bomblets carrying HEAT charges over an area. However to counter the planes, mobile anti-craft guns and mobile sams were made to counter the planes and gunships.
Well it would be expensive first of all.
Also there would clear countermeasures as Harm had explained. There could also very well be counter-drones used to stalk our own tanks.
But we already have anti-ground aerial vehicles.
A-10 Thunderbolt II. It's a serious beast, 30mm Gun, 11 hardpoints carrying fuel tanks, missiles, bombs, etc. Only one crew member flying each plane, and it's got some serious armor. Plenty of A-10's have been shot apart and still able to fly home or at least crash in a recoverable zone.
As much as love the 30mm gun, it was made to strafe convoys. The real tank buster is the A-10s armament of cluster bombs and the guided missiles that it carries. In a shooting war, most of the Apaches and A-10s would have been shot down by weapons like the Tunguska or Buk.
