Does it really matter, i.e. make good writing bad or bad writing good? IMO whether the physics is correct is mostly irrelevant (and it almost never is). It is enough that it is somewhat coherent, even failing that is not necessarily fatal, while it is crucial that the psychology works. The latter is often a problem when the current social environment of the author is just transported unquestioned into a fictional universe. Thats why IMO a lot of fiction (IMO including a lot of 'classical' SciFi) doesn't age well (or sometimes feels already outdated when first published), while e.g. Lem or Pratchett are much more resilient to differences in reader's perception. 'The Dispossessed' is also a very good example of timeless fiction, because it stands on its own and doesn't need any implicit assumptions about society that the reader may not share.