Not a typo, they've been powered off for around a decade. But HDDs (just like floppies) don't lose their magnetized property in just 3 years, or even 10 years,

Not a typo, they've been powered off for around a decade. But HDDs (just like floppies) don't lose their magnetized property in just 3 years, or even 10 years, barring the very rare case of an extreme fluke or environmental exposure. Flash memory (memory cards, USB sticks, SSDs) loses electrical charge relatively fast, however. That might be what you're thinking of.