There are RC aircraft with collective pitch controls, like most RC helicopters and even some multirotors. These RC aircraft generally can autorotate, as well as do things that are probably not practical for full-scale aircraft to do, like fly upside down. :)
A collective pitch quadcopter flying upside down: https://youtu.be/MVL_Hf4ilLg?t=162
An RC helicopter doing, well, all sorts of acrobatics that hardly make sense: https://youtu.be/KmPchrGW1TQ?t=48
An RC helicopter autorotating: https://youtu.be/bxQ5kwqiPN4?t=136 (this one has an internal combustion engine, although that shouldn't make much of a difference for autorotation)
Just a guess: stronger strength to weight, and power to weight ratios, compared to the real thing. The tail rotor in particular appears to be quite a bit more powerful for the weight of the model than would be expected in a full size aircraft. And then also, these kinds of movements with a person inside? Haha! No!