That's not to say I couldn't imagine that someone, somewhere, wakes up to an alert one day that some control board has failed, and it's _just_ the CPU, and the spare parts bin for out-of-production components got water in it and is ruined, and the company is losing millions per hour the system is down. I just don't think that'll be a common story. With full faith in humanity I like to imagine instead that the people responsible for such systems have planned for full control board replacements to be available for use comfortably before unavailability of the Z80 risks a significant outage due to component failure.

A LOT of them. Zilog only announced its discontinuation in 2024.

But that also means that there are A LOT of them out there, and they are cheap and generally extremely reliable parts. So if you rely on a device with a Z80 in it and you're worried about the CPU failing you can have hundreds of these things on the shelf for ~no money.

So I would say it's of limited utility for industrial applications for now simply because scarcity is not an issue for the real thing. This might change in the future so it's good that projects like this exist.