Quoted By:
We kind of do have mech animals with planes
Animals routinely fall over and trip on shit and they have massively optimised brains for motor control. Luckily they're incredibly tough, programmed with reflexes to fall with minimal damage, and can heal.
Piloting a mech animal would be even harder than piloting a human shaped mech, as it's an entirely different set of instinctual controls to learn. Piloting a human mech would require an incredible level of skill and awareness compared to a box on wheels or a box on rails, let alone a fucking emu or 4 legged thing. You'd need neuro-interface for any reasonable degree of safety, reflexive reactions and situational awareness, and pilot training would be very expensive
And what's the use case? We can helicopter in, parachute or drone drop equipment to inaccessible areas and send men in by foot with climbing capacity. Anywhere you would need to climb a walker wouldn't really be able to access, unless it's some kind of jumping flea which sounds insanely dangerous. We have road making down to a fine art - chop trees, drive in a bridge layer, bulldoze debris and suddenly thousands of wheeled or tank-treaded vehicles can roll in.
And finally parts would be insanely complicated for a walker. Think of the engineering feat to put mechanical legs with fine balance control with a useful power source, weather sealing, protective fairings, shock absorption etc and have room for a human + whatever cargo necessary. That's a very complicated bit of kit needing very specialised technicians, oils, servicing etc.