He's using the subset of familiar technology as evidence that we've not lost it. But there are two massive super-sets that have been lost : (1) recorded & observed artifacts with unknown origins and (2) destroyed libraries and manuscripts
Even in the past 20 years the Iraqi Archives & Mosul Library were destroyed -- not to mention dozens-to-hundreds destroyed since WW1 , as well as many destroyed in ancient conflicts.
"do you think we had anything important in there?" -- "not possible, we've got everything we need already"
In other words, we don't know what we don't know because it's been destroyed and so have our records of it.
Even in the past 20 years the Iraqi Archives & Mosul Library were destroyed -- not to mention dozens-to-hundreds destroyed since WW1 , as well as many destroyed in ancient conflicts.
"do you think we had anything important in there?" -- "not possible, we've got everything we need already"
In other words, we don't know what we don't know because it's been destroyed and so have our records of it.