rocks can get pricy when you start trying to make them streetable with wheel brakes, manual hubs, etc. but to bring a d60 up to the strength of a rock you're still going to spend a lot more overall.
even fully built, you're still going to have inherent limitations that will always make the 1 ton weaker such as ring/pinion size etc.
for a trail only rig, rocks can be FAR cheaper than 1 tons.
