> The only real scarcity would be of a long attention span.
I get the author's drift, and broadly agree. But I don't think it's really a long attention span that would get in the way of (e.g.) a Mars colony, or interstellar travel; it's that people's views change from one generation to the next. My kids have been imbued with some of my attitudes, sure; but I've not had much of a hand in the raising of my grandchildren. And kids rebel against their parents' views, even if they're objectively less sensible than the latest kids' fashion.
The Death Star, to take the author's example, is the product of a particular hypothetical society that looks a lot like fascist authoritarianism: a Glorious Leader, militarization, and oppression. But how many societies like that have lasted 500 years? The Golden Horde lasted about 250 years; the Roman Empire lasted about 200 years. Chinese imperial rule lasted much longer, maybe 1,500 years? Egyptian pharoahs about the same, if you treat the Early, Middle and Late as distinct empires. But these empires changed their character as the centuries passed, and were not characterized by any particular continuity of social outlook or collective goals.
I have only a vague knowledge of what the attitudes of my grandparents and their generation were - too vague for me to either support them or to rebel against them. So I think it's not so much a matter of attention-span, and more a question of plain old memory; history lessons and books are no substitute for talking to the people who were there, and after 200 years there's nobody left who "was there".