The Macguffomatic was forged by dwarves, who have a viciously strict “2000 year warranty” policy.
The Macguffomatic was specifically designed to withstand lack of use for millenia because it was designed to combat a threat that could show up thousands of years in the future.
The Macguffomatic was contained in a stasis field.
Inverted: "Behold, the Macguffomatic! This thing is so foolproof, it'll still be running 2,000 years from n- uh oh. it was working this morning..."
Subverted: Turns out, the Macguffomatic is only cosmetically functional. It breaks the moment someone tries to use it
Double Subverted: The malfunction turns out to be part of the still-functioning security system.
Parodied: The Macguffomatic is revealed to be older than the universe itself. It still sparkles and a character comments that it has that new car smell.
Zig Zagged: The Macguffomatic looks functional, but breaks the moment it's used, but it's part of the security system, but the whole thing was actually being maintained by a secret legacy, but they abandoned it a long time ago.
Averted: None of the ancient artifacts encountered are technological enough that they'd be expected to have broken down.