> Does this also mean only using "standard" parts? Or does the manufacturer have to over-produce the parts for, lets say 7 years, and then warehouse and ship those parts, probably multiple times. Or keep a low rate production line running for 7 years? What happens to the parts that don't get used? Are they scrapped?

None of that is relevant in this context: The parts are available, but the laptop is designed and built such that the alone keyboard cannot be replaced.[1]

[1] Not sure if this is possible on that specific laptop, but with a steady hand, a tiny drill, maybe a magnifiying glass too, you can maybe drill out the rivets, then replace the keyboard, then either re-rivet it back again or tap very tiny thread into the laptop and use screws.