Edit: I see there's this response video https://www.youtube.com/watch?v=9b9LahaBJIk about how you're actually supposed to climb these. With safety.
I note they also brought a long enough rope to haul the tools up once they got to the top. That seemed to me the stupidest part of the original no-safety video.
The roller will keep rolling as long as you pull away from the ladder. If you drop down, the roller will hang. I've done one spring of snow cleaning from roofs and we had a bag full of different rollers (different standards). Only had problems if the rollers were left wet and they froze. Are they not mandated in the US? Time for someone to start a business...
Good question; I don't know enough about the specific industry to say. Knowing what I do about industry in the USA in general, I suspect that anything that must be installed on the structure, and isn't required by OSHA or by insurance companies, will not be. Aside from the expense of retrofitting, the safety rail is then one more system that must be regularly inspected, maintained, and insured.
Actually I suspect that facilities for which actual employees do most of the high work, would install these systems. Transmission towers seem pretty low-maintenance, so their high work is probably done by contractors. Those guys can worry about themselves.