Thanks again folks...it seems amazing that the “technology” never progressed beyond the limited use of copper...by the sounds of it, they never even discovered bronze which was discovered soon after copper in Europe...
I've read a few books related to the subject. One reason was the limited state of agriculture (plants and animals) in the pre-Columbian "United States".
Despite fertile soil and biodiversity, very few plants in what became the United States stood out as suitable for surplus-level cultivation. If I recall correctly, corn/maize is the only native cereal grain. There was a type of rice that grew wild in limited areas and was gathered but not cultivated. The list of native edible plants suitable for intensive farming given other constraints or alternatives was very short. But, hunting/gathering resources were abundant (the early Europeans were in awe). There was another big obstacle:
A lack of animals that could be domesticated for agricultural purposes.
Species that were good candidates for domestication were geographically limited (e.g., mountain goats in the far northwest and bighorn sheep in the Rockies) and that just didn't take hold. There's some evidence that a few species existed that were good candidates for domestication before the Europeans arrived, but qualities that made them good for domestication also made them easy to hunt right into extinction.
No pigs (domesticated or wild). Eggs could be eaten from native birds, but that process looked more like hunting/gathering. No domesticated chickens. Milk? No cows. No domesticated goats or sheep.
There were no pre-Columbian draft animals. Remarkable! There's no need for a large/strong/sharp plow when you've never seen a large animal that could be domesticated to pull a plow. That also means no draft animals to pull stones or timber. Clearing land and mining would have to be done by hand.
Even along the Mississippi River where intenstive agriculture was practiced and maize was highly productive, it was all limited to what could be done by hand. The exchange of effort for calories was still dependent on time consuming hunting/fishing and gathering.
High surplus high protein agriculture was not widespread or even possible in most places and that put a damper on the ability or need to specialize in metallurgy.
Along with the lack of other draft animals, there were no horses or other animals for transportation! Native North American people didn't have anything to ride other than small boats. North America is not only huge, it presents large, challenging forests, deserts, rivers, and mountain ranges.
Trade meant taking what you could carry. Walking or traveling in small boats. The day before Europeans arrived in what would become the United States the state of raw materials trading was nothing like what had been going on for thousands of years between and within Europe, Asia and Africa.