Also not addressed is recycling. If you wear out same goods you can landfill it or recycle it. if we care about copper running out this matters. but as the article notes copper is a tiny amount of total material used, even though we should worry about running out.

I have never heard of “material footprint” and from the definition it seems entirely worthless. The article doesn’t start with any reason why anyone would be interested in this measure, just that comment it is starting to show up in reports.