they should be able to. same physics applies, right? poles dont have to be as thick or as deep to resist the same torque, and if you could somehow make the pales curvy/corrugated, they could be thinner, too.
Wooden fences tend to be only a plank thick, so there's no savings like there are with brick walls where the savings come from getting to build a single layer thick.
Raw lumber is much cheaper than sawn lumber, though. It's OK to use more, as long as the volume increase and price decrease works out favorably.
Yeah exactly… I guess there might be some waviness/height/length ratio where the extra length and the absence of posts evens out.