In the new Star Trek movie, Spock says that a "supernova threatened the entire galaxy". Yet in various TV episodes (notably ST:VOY - The Q and the Grey) only those ships and planets that were in close proximity were destroyed by supernova explosions.
However, the following source says that a supernova 3000 light years away could dump a 1000 solar flares' worth of gamma radiation on Earth. This source argues that Romulus, Kronos, Vulcan and a number of other worlds must be within 200 light years of Earth.
Does this mean that the supernova that destroyed Romulus was going to destroy almost all the federation planets, its allies and its neighboring enemies? Or the entire galaxy? If so, how did the Delta Quadrant survive multiple supernova explosions with hardly any destruction (in the Voyager episode mentioned above)?