It's been my experience in building construction use of piping, that the bends are the weak point. Second is the area next to the welds, which has rings of different grain structure and hardness.
Design pays a large part of the process. Some crush makes sense. A totally rigid construction, would likely want to separate at the anchors.
I wonder why nobody has experimented with a fiber foam filling for the pipes and tubing after construction. Which would be lightweight, add to rigidity and likely help prevent kinking.
Gussets (even ribs) and fill, would probably double the unit strength, with little weight penalty.
My brother ran into a boulder at 80 MPH, with his buggy, the frame and cage was made of black steam pipe, the construction used a lot of triangulation and had few bends. The front axle ended up under the drivers seat, cage intergity held.
Bends look pretty, triangles are stronger.