"The Man Who Sold The Moon" is the title story of the first volume of Robert Heinlein's Future History. Genesis, a late novel by Poul Anderson, is a single volume future history. D. D. Harriman, the entrepreneur who "sold the Moon," lived underground because, despite its suitably comfortable interior, his dwelling was an elaborate nuclear air raid shelter. Laurinda Ashcroft, a human-AI interface in Genesis, lives underground because the ecology is planned. Thus, these works reflect the concerns of the different periods in which they were written.
When Laurinda receives a visitor in her underground home, there is, for me, a faint echo of Delos Harriman's conversation with his wife in their underground home but the most notable feature of these works is the many differences between them. Harriman and Laurinda inhabit earlier and later periods of different fictitious timelines so they cannot meet except in the imagination of a reader who sees some tenuous connection between them.
Another measure of the distance traveled by future histories is simply the vast difference in scope and scale between Heinlein's Future History and Anderson's much longer History of Technic Civilisation. In the Future History, capitalism develops the Solar System but becomes oppressive. Social disorder on Earth leads to an American theocracy. This is followed by the Covenant which, after some further troubles, leads to a "mature culture." In the Technic History, capitalism develops a vast volume of interstellar space but becomes monopolistic. Social breakdown in the Solar System leads to an Empire which lasts for several centuries and volumes and is followed, after the barbarism of the "Long Night" period, by the bigger and stabler Commonalty.
"If This Goes On -" is the first of only two novels in Heinlein's Future History. Ringworld's Children is the fourth novel in Larry Niven's Ringworld Tetralogy and maybe the eleventh novel in his Known Space future history depending on how we count them. (There are works written by Niven, co-written by Niven and written by others.) "If This Goes On -" occupies partly familiar territory. All the action is on Earth and Americans still go to church. If anything, sociologically, they have moved backwards to a form of medievalism with the Prophetic priesthood misusing modern communications technology until they are overthrown by the Second American Revolution. By contrast, Ringworld's Children is set not only much further in the future but also not even on a planetary surface.
Several intelligent species contend in the space around the Ringworld, sometimes using anti-matter as a weapon. A ghoul protector uses nanotech to move the Ringworld out of Known Space through hyper-space. At least three terms here require explanation: Ringworld; ghoul; protector. But my point is simply the vast distance traveled conceptually and technologically from "If This Goes On -" to Ringworld's Children.
However, both Anderson and Niven have written in an American future historical tradition initiated by Heinlein. Without Harriman and the Prophets, there might never have been a Technic Civilisation, a Laurinda or a Ringworld.