I think they mean that they were the last generation who was alive and learning about how things were built and innovated on, while newer generations won’t have that benefit.
They will be exposed to high level tools instead that automate a lot of the work which will make things easier for them but reduce understanding.
Thus, the newer generations on average will need to purposefully dig back into the past to learn what the older generations learned by just being around while it was happening.
These are just general trends though, its not going to be very practical to try to apply it to any individuals, or the group of people you work with.