To a general audience, an interstellar war that might happen is an abstract threat that has no visceral effect on the audience. The ship crashing into San Francisco is much more relatable to the casual viewer.
I don't refute that. My point is that it has nothing to do with Lindelof's attempt to explain it in terms of movies requiring the fate of the entire world to be at stake. How does a ship crashing into San Francisco represent a bigger
danger than Lex Luthor causing California to fall into the ocean? Lindelof is contradicting himself.