It could be scaled up if instead of the works running on rails they sat on wheels and hauled themselves along on fixed wire ropes. That would leave the problem of supporting the wires and pipes.
I have dairy farmers as relatives and used to help them with the hay bales but this was discontinued twenty years ago. They went to "big" bales (The round ones you see wrapped in plastic in fields.
Its the silage that I am interested in, the grass is cut and chopped in a machine behind a tractor then blown into a trailer also pulled by a tractor. Depending on the distance to the silage clamp, another tractor and trailer would be in use, traveling back empty to the field so the tractor doing the cutting and blowing does not have to stop.
In a good season a farmer might get two cuts of his grass but it is normally one. Other things to remember, is that the weight of the tractor causes soil compaction and a loss of fertility and the shorter the grass the slower its rate of growth.
So I was cogitating on putting stakes say 2m apart withe a chain between them right across the two ends of a field. Then have a light weight machine that start of at the first stake and pulls it self along a cable going across the field cutting the grass as it goes and loading it into a box or bag. which it drops at the end of the field. It then unhooks the wire rope travels side ways along the chain, reattaches the rope and makes it way back, cutting as it goes. When it gets to the end , it again travels sideways reattaching the rope then forward cutting as it goes. If its set to work every three days then there would be no reason the chop the grass and the growing grass blade would be at a better length for growing. So every morning the farmer would remove a few cubic metres of sileage, move the machine into a different field and refuel the machine then go back home for breakfast. Being a robot, it could work through the night.
Frank