It’s not about the number of years, it’s about how accessible the original title is. The less accessible, the better you can justify the existence of emulating that title
I think we all know the “preservation” argument is bullshit. I don’t know why we keep pretending. 99% of people copying games are not “preserving” them, they’re playing games they didn’t pay for.
Whether or not you think it’s wrong to do so is another argument. But can we just start being honest with ourselves? You’re not opening a museum, and you know it.
It’s not about either of those. A system emulator is nothing more than a program that converts the hardware instructions of one piece of hardware to another. What you DO with that can be legal or illegal, but the emulator ITSELF is totally legal and requires no justification.