At least this material has a main ingredient that is renewable. No part of steel is renewable right? You can't grow more iron ore (though there is a lot of it lying around).
Also I'm doubting "minimal processing" for steel. You have to dig up the ore with giant machines, transport huge amounts of it by train, smash it with a lot of energy and heavy equipment, melt it with a lot of energy and heavy equipment, etc., etc. This seems like the opposite of minimal?
Wood also requires heavy equipment to cut, mill, process. Not to mention, it needs a heck of a lot of land area. In addition to whatever process is involved in "hardening" this wood.
Plus, steel is entirely recyclable. And it has some natural properties that make is relatively easy to recycle. It can be sorted with magnets, and it has a higher melting point than most impurities.
The ball of iron would be Earth's core, and between the thin crust on which we live and the iron core there is the very thick mantle.
Nevertheless, the mantle is made of a mixture of iron oxides, silicon dioxide and magnesium oxide, with small quantities of the other elements, so under the thin crust, even if there remain thousands of kilometers until the iron ball, there is nonetheless what is essentially a huge amount of iron ore.
On earth it replenishes too via meteorite strikes and by nuclear decay. I'm not sure was decays into iron, but I'm sure it's most things, given its name as the most stable element
Also I'm doubting "minimal processing" for steel. You have to dig up the ore with giant machines, transport huge amounts of it by train, smash it with a lot of energy and heavy equipment, melt it with a lot of energy and heavy equipment, etc., etc. This seems like the opposite of minimal?