Why Walking Tanks are less practical in real life
Although slightly more reasonable than the humanoid Humongous Mecha more common to Japanese media, these still mostly fall into the Awesome, but Impractical category, and thus this trope owes its existence primarily to the Rule of Cool. The idea is problematic because mechanical legs sturdy enough to support a heavy vehicle would be bulkier and heavier than a track system, increasing the vehicle's overall mass and the amount of power needed to move it. Another concern is ground pressure. You often see designs where the foot contact area is small in proportion to the weight they transfer into the ground, and not all of the feet are in continuous contact with the ground while a legged robot walks. A walker could therefore be more prone to sinking into soft ground. And crucially for military use, putting a vehicle up on legs raises the body higher off the ground so that it becomes a more prominent target, at least in open terrain. In Real Life, the history of tank design shows a move to make them lower profile so that they present less of a target. The legs would also need to be armored to at least some degree—which would be weight inefficient from a surface-area-to-volume perspective—and a tall walker would face a more damaging fall if the legs were shot out from under it.
The main justification for a walking tank would be the ability of legs to handle terrain covered with such dense obstacles that even a tracked tank couldn’t traverse it, or perhaps wade across rivers that a tracked tank would need to snorkel through, but modern armored forces are used to dealing with or working around such situations. Granted, the high ground clearance could protect the crew better from the blast of land mines and IEDs, but that’s negated by the exposure to enemy direct fire, potential damage from falling, and the difficulty of escape if the crew needed to bail out. There would also be a larger number of moving parts that could fail, and swapping out a busted robot leg would be much harder in the field than swapping tracks, road wheels, or torsion bars.
In short, the benefits don’t outweigh the drawbacks. That being said, walkers could prove useful for certain mundane logistical purposes if the basic engineering problems could be solved.
