If it doesn't have to carry people, it can carry much less armor, which makes it more maneuverable; it might carry so much less mass that it doesn't need tracks to handle rough terrain. If it's light and nimble enough it doesn't need a turret to point the main weapon.
Is a remote-controlled dune buggy with a low-recoil rifle a tank?
You still need to protect the ammunition, otherwise a nearby explosion will set it off (this also happens at the moment but less so than I would expect it to happen with less armor, which also would make penetrating the wall much easier and which would make the tank a softer target altogether).
- you can airlift 25 2-ton dune-buggies instead of 1 50-ton tank
- you can buy 25 $2 million dune-buggies for the cost of 2 $25 million tanks
- if you sent 2 tanks, losing one is half of your force projection. If you sent 25 dune-buggies, losing one is 4% of your force.
- maintenance on an unmanned 2-ton dune-buggy has to be easier, faster and cheaper than maintenance on a tank. Tanks need dedicated recovery vehicles (or Ukrainian tractors) that cost nearly as much as another tank. Maintenance is going to be much, much easier without armor and the concomitant suspension for the armor getting in the way.
A hybrid powerplant is probably best -- a diesel motor-generator to charge batteries and run for distance, with an electric motor system and nice quiet relatively cool batteries for an hour or two of sneaking around at a time. Tanks don't sneak up on you, but a hybrid dune-buggy in battery mode can.
This also has knock-on effects for the civilian economy, because if the cool support weapon for the infantry is a quiet hybrid dune-buggy, the same thing with a crew cabin instead of a gun and ammo will be a smash hit.
The tank can carry a bigger gun, but that's about it. Most of it is armor that it has to haul for 100-300 miles at a time (before it runs out of fuel).
Also, lol at "Ukrainian tractors". Their biggest (only?) tractor plant was destroyed in Kharkiv. Most of their tractors are... John Deere. Probably why they got so good at modifying them that Americans are buying their software :D
But we already know that tanks are vulnerable to relatively cheap small vehicles, so this is not a comparative disadvantage.
Also consider that tanks are dispatched in small groups; they need to be able to defend themselves. But a swarm of buggies could have weapons optimized to defend each other -- a shotgun is pretty effective against small suicide drones, and nothing defends against a laser-guided bomb anyway.
Is a remote-controlled dune buggy with a low-recoil rifle a tank?