> In June 2018, the machine mysteriously disappeared
I don't think it's mysterious. The owner likely ran out of full, rare cans of soda and could not / did not want to source them anymore.
For folks who aren't aware your local distributor cans / bottles a much wider variety of product than what you find on typical grocery store shelves. If you have a commercial account with them you can get the list. Sometimes they make special runs for a promotion, special event, or special client order. Depending on the circumstances and if you have a good relationship with your sales rep you may be able to get notified and grab a case or two.
It is possible they were vending long expired drinks... but it is also possible they simply had a hookup at the distributor and sourced rare drinks from time to time.
Supposedly, you could order Crystal Pepsi, but nobody did, so none was made (except for a brief period a couple years ago).
Works this way for tons of things. People would be surprised the kind of things you can get by being generous to sales reps.
I stepped into my office 6 months after covid WFH started. All the unrefrigerated sodas were flat.
I doubt they had expired drinks with no complaints.