Let’s keep in mind that Tesla invested in this truck to be the next F-150, which is the best-selling vehicle in the USA for the past multiple decades.
Even the hated Edsel is worth quite a bit today.
Of course it might be harder to keep a Cybertruck running for 50 years due to all the computerized components. Restorers will probably be relegated to rebuilding Cybertruck bodies with new components.
Really no different than any classic car, really. GM isn't selling OEM parts for a '57 Chevy, for example. If you need replacement parts on those, nowadays, you're likely going to specialty manufacturers given there really aren't any "parts cars" around anymore.
Tesla’s corporate leadership would be much happier if the Cybertruck was selling 100,000 units a year and was not at all a collector’s item.
Good book on the subject: https://www.sup.org/books/history/disaster-dearborn
And all the well-documented reliability and quality issues.