then they just stopped allowing 3 wire feeders to additional buildings altogether.
When I went to school, they taught that, if a neutral and ground were both taken to a barn, they must be tied together and ground rods installed. The instructor said it is known that there is a parallel path but it is better than what can happen if they aren't tied together.
This is what can happen if they are not tied together:
You can lose the ground connection and never know because everything still works. Then, if there is a fault from hot to ground, the breaker might not trip.
With a water bowl frame tied to hot and the cattle standing in their wet poop, they will be electrocuted.
If the animals don't get it, a farmer or electrician might turn the power off to a piece of equipment but when they open it up, there is voltage between neutral and ground.
Why are we going back to a proven failure?
