alt Hacker Newsit largely depends on the metal but the issue is with quality, not amount. plus, you don't have much in the way of just iron items these days - you have steel which requires temps quite a fair bit above what's possible in a charcoal/coal-based forge to work. early copper metallurgy utilized ores that were 10%+ metals - much softer, more malleable. these days we work with less than a single percent (but from much larger veins). much smarter people have written about this than me: https://ui.adsabs.harvard.edu/abs/2025GsGe....400323M/abstra...
a better focus would probably be on the fact that there's no longer really easily accessible coal anymore, much less oil. there also are far less trees by which you can make charcoal and firewood (except in certain areas) and that's actually fairly important when it comes to crafting and technology: https://www.postcarbon.org/can-civilization-survive-these-st...
If human society collapses, our cities and landfills will become ores. Strange ores filled with unnatural mixtures of metals, but ores nonetheless.
The sources you've linked discuss mostly the recovery of additional metals on top of what we have already recovered. That's a different and much harder problem. It's worth remembering that historically, the amount of metal obtained was much smaller — the vast majority of the copper that has ever been mined was mined in the last century, even though humans have been using copper for thousands of years. But historically, that copper was mostly used for consumer products, while today it becomes electrical cables, so it's less obvious how much copper we all use. There's surely enough copper in the walls of my apartment for everyone living here to cook in a copper pan, even though we think of copper pans as being too expensive nowadays.