Maybe the past isn’t as revealing as looking at products available today. “What today will last 100s of years?” As a quick and dirty example, I can think of a ton of amazing things made from materials that weren’t commonplace in 1800 or 1900 - A titanium bike frame should last 100s of years, but it will be obsolete before it falls apart. If the pace of changes continues to accelerate, trying to design something that lasts 200 years seems rather futile (besides interstellar spacecraft?)… better to design the society and systems to make reusing materials the norm rather than the exception!
Also, look at Patagonia’s new initiative to reclaim and recycle down - pretty telling of down’s capability to last.