UAVs are highly susceptible to wind and drift, especially indoors with no GPS, and while DJIs collision avoidance is pretty good, any land based vehicle won't (fatally) crash if it touches anything.
The critical consideration is that movement is dangerous, under conditions of pervasive battlefield surveillance, so when it is possible at all it must be exploited to its full potential, and thus can be conducted via an expensive process such as flight. In turn, to make movement dangerous to the enemy, one must make terrain frictionful to cross, through high lethality, low detectability assets, of which mines are the paradigmatic example.
[0] Brief bursts of flight interwoven between slow stalking of different ground locations for worms.
How would you counter? Up-armoured bipedal robots with roughly human-shaped heat-signatures is the only thing that would defeat easily-implemented automatic counter-measures. But if the "minefield" is under surveillance + command and control, then that goes right out the window. Besides, the cost-benefit (let alone logistics) is firmly in favor of the defender's "robins". I suspect attackers will try jamming signals and then send in the meatshields.
Ugh.
(If not that, a small nuke can generate enough heat and gamma rays to burn everything near the point of the blast, but the military escalation hasn't reached this point just yet.)
I had another thought. There's a tried and tested method for knocking down bird-sized moving objects. So, what about shotguns? (Yes, I know they're currently banned for combat use. I think something like this would override that, at least de facto.)
With something cheaper that you spread around. Drone grenades?