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
- 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.