rockm
Spuds Moyogi
It has to do with the size of the cholla that grew around the skeleton. Cholla can get VERY big and old. Some can be over 13 feet tall...Just realized that different species/varieties of cholla, relative to what @rockm pointed out, likely would have different characteristics of wood, because the stuff that grows around here certainly isn't like the stuff in @nuttiest's OP pic. It's very possible that the stuff around here is so flimsy because that's just the variety.
Still, looking for stuff to do with the kids over summer, and this is as good an excuse to hit the hills as anything.
Nocturnal Scene Fact Sheet
www.desertmuseum.org

Cholla Photos: See These Amazing Desert Cacti
Spring has once again returned to the deserts of North America and with her return, so too has the amazing colorful blooms of desert wildflowers and cacti.
FWIW Old "cactus wood" is more durable than younger. Thicker skeletons are more durable. FWIW, saguaro also makes "cactus wood". Saguaro ribs have been used for roofs on traditional houses in Arizona for quite some time, either in the ramada-style which is basically a lathe roof, or for the skeleton for adobe.