Why our ancestors used copper utensils?

Has it ever occurred to anyone that out ancestors were human and used the existing knowledge, It may have been the best at that time.
Did our ancestors know of Stainless Steel? Did our ancestors know of lead poisoning? Did our ancestors know of cell phone, computers or movies? If our ancestors were god why did they die?

I am sick and tired of these stupid posts repeated thousands times.
If our ancestors were so smart why did they die, why there knowledge was overtaken by modern marvels?