Did you check out the tires?
And that occasional rain in the desert ~ I proposed a large plastic bag to protect the bicycle until it drives up, which it will, with more certainty than a snowstorm melting in a cold winter.
It doesn’t cost that much more than cardboard, and it doesn’t have to be welded (I know a guy on the bike trail with a hand built from scratch no welding bike), and it will last much much longer. The tires didn’t look that exciting.
I live in the desert, we finished our rainy season last month. A cardboard bike would have to be in your plastic bag for 4 months. If it’s a primary transportation option having it unavailable for 4 months isn’t really much of an option. And of course the fact that the rainy season ended didn’t keep me from getting caught in a cloudburst Thursday.
This is an attempt to solve a problem that doesn’t exist. There are tons of cheap materials to make bikes out of that last longer. They’re what these poor areas are already using.