Even NASA was unable to establish contact with the IMAGE satellite after 18 years. I do see the false equivalence here, yet it is nonetheless thought provoking, alongside 100+ year old tea shops in Japan.
We absolutely could still make a fancy gauntlet that stood a good chance of lasting 700 years, but it would cost enough that only today’s wealthy knights would want to buy it.
Planned Obsolescence is an urban myth - there may be some examples, and if there are that's a tiny slice of the market. The reality is what OP said, price and quality are tradeoffs. Manufacturing things that can last 100+ years of wear and tear means those things would be costly, with very limited use cases.
Maybe it is a creeping anxiety about losing knowledge as we stride forward and forgetting the means of recreating the things we end up with. Kind of like the Dark age of technology in WH40K.
https://en.wikipedia.org/wiki/Eiffel_Tower_replicas_and_deri...
But for more mundane stuff, even phasing out media storage technology periodically causes a giant loss of knowledge and means even with the help of archiving groups.
I also stated that I'm ambivalent about the worth of such knowledge preservation, whether it is a form of stamp collecting or something more foundational. All I have to compare is the fact that we have an estimated %1 of Ancient Roman literature surviving and I'd prefer to have at least a bit more of it.
I do admit I didn't have a point to make really, or to assign worth to an ancient gauntlet. Rather it was a reflection on losing stuff while finding stuff and the permanence of marks we leave on this world.
I hate that I have to put the disclaimer here that there are obviously costs to the planet and us for this achievement, but it is undoubtedly what characterizes the age we live in (late-19th century forward) in a way that is arguably (if not self-evidently) heretofore unseen in all of human history.
Today we have much tighter engineering tolerances for cost reasons.
Surviving Roman infrastructure didn't just sit around for two thousand years, it has actively been maintained in that time.
You'll find that you can keep a lot of grandfather's axes around for as long as you want, as long as you keep them clean, and replace the handle and the blade regularly.
Sometimes things are built well or kept around for whatever reason. But most of the time people slap it together and call it good enough. Then when they are done with that item it is discarded.
You can say 'look at all the stuff from the roman era that survived'. You can also say what about all the stuff that didnt? Probably most of it. But you do not see it because it is no longer there.
Hopefully the constructions (both technical and social) where we store it, in the hope of a future generation that can rid of it, will last centuries too.
I'm convinced everything surrounding nuclear waste is where humans are putting the most effort in thinking and planning for ages. Or, I hope it is.
That said, someone once told me that e.g. castles "back then" where built for centuries, not decades. People thought much more in family-lines, generations and long lasting tribes, than individual, or families' lives.
And there too, nuclear waste is where current society had to think of the grandchildren of the grandchildren, rather than 'before I die'.
How many generations of humans have been writing software? Three?
We're at the early stage of software engineering; brittle code is not surprising.
There's also Voyager, 46/7(?) years and counting.