Games

That's not the point of it though. Not about whether you could fix or maintain it when operating it, it's about not operating it if presents a notable risk of failure. The Smithsonian doesn't start grinding cornmeal in a bowl from the Mississippians. The Connecticut Museum doesn't take it's colt rifles out the range for target practice. These organizations would use a replica to demonstrate what it was like, as opposed to risking damaging an original article.

Thats also not even necessary true either. While they may have invented there various consoles, at some point it will be nearly impossible to acquire replacement parts. They don't manufacture the ICs or mainboards or the various discreet components. So if there's no old stock, how would they "fix" a broken N64 (or later) console? It might be theoretically possible to fab a NEC VR4300 to replace a dead one, but probably cost hundreds of thousands, and it wouldn't be broken anyway if you hadn't left if running 16 hours a day so some sweaty tourists could play on real hardware.

And why would they? It would cost more, be more work, and have less reliable results than using a completely replacable computer running an emulator. The entire consumer facing side of the equation is worse if they run the games on the actual hardware, as long as the consumer doesn't see it, which is really down to how they design the exhibit.

Do you think the public is understanding enough to accept that "The NES is really old and it broke so you can't play super mario bros today", when it's the only day you are gonna be there? Temper tantrum, bad reviews, loss of face. From what I understand, Japan actually cares about all that, so Nintendo probably does as well.