Kinda mind-boggling how this has been parodied since forever [0], yet is still true. And we're not even talking about the Soviet-style production organization where frugality was never paid more than lip service: you'd think that in a competitive environment there'd be enough pressure to save up on the input resources wasted.
The linked article in turn links to a research paper at https://www.woodresearch.sk/wr/201202/12.pdf, and while that paper does support that only ~20% of a tree gets sawn into long pieces of (construction) lumber, it absolutely does not support that the remaining 80% is waste. For example, ~37+9= 46% goes to the production of chip and particle boards, a decent amount becomes firewood, the paper industry takes some "waste" wood as input for cellulose production, sawdust has a variety of purposes and even the leaves and stumps can simply be composted.
While coppicing does results in fairly straight trees, they're still circular and will result in large amounts of waste if you try to cut dimensional lumber out of it.
Any time you find yourself surprised by a claim, that's your signal to dig into the sources.
I live in BC and a huge portion of the tree is left in the forest. All of the branches, smaller trees, tops and other bits not worth transporting are burned in slash piles or left in the forest to decompose. There is typically at least a foot thick layer of wood debris left in the cut block after the logging companies come through.
Some forestry companies near me allow firewood processors to come through and grab the leftovers out of the clear cuts, but it is pretty close to a rounding error.
Going by volume is also remarkably useless because if a tree produces some large non-dense structure like a leaf it skews the numbers. The issue with industrial forestry isn't waste, but monocropping and habitat destruction.
In general, salvaging material from construction demolition isn’t worth the time, with some exceptions like copper. The metal and concrete will be recycled, everything else is garbage.
Gypsum wallboard aka drywall is used because it’s cheap, light, it’s easy to install, and easy and cheap to finish.
For wiring at least, the wall itself isn’t the enemy, that’s easily navigable with a drill bit and fish tape, it’s the dang ceilings that complicate things. ACT grid ceilings make adding receptacles or switches into a finished wall pretty easy, you just drill into the wall, cut an opening, and use a fish tape to pull in your wire or cable.
The best real-world, not made-up example of "circular economy" is the Japanese women who work as prostitutes in order to make money to spend on their handsome bar-provided boyfriends. Lmao.
Also, do we really want to build houses that are meant to last 2000 years? It seems expensive and very impractical when you want to tear it down to build something new.