A reality where Romulus is destroyed doesn't seem as interesting a reality where Vulcan is destroyed, on the principle that stories are better when the heroes are the underdogs. Amps up the drama that way. (Think about fictional stories across the whole range of TV shows, movies, plays and books - almost always, the protagonists are at some disadvantage. It's a tried and true strategy for holding people's interest.) And then there's the pragmatic factor that it's far more likely Trek on TV will key off success (Abrams' movies) than failure (Berman's TV shows). Hollywood no likey failure.