They are distributed everywhere. These three are among the oldest and presumably of similar age to other "oldest" stars in other galaxies. I take it to mean ma

They are distributed everywhere. These three are among the oldest and presumably of similar age to other "oldest" stars in other galaxies. I take it to mean many galaxies have surviving stars from the population of stars expected to still exist. Honestly it seems obvious. Any given galaxy will either be as old as those stars, formed from the merger of other galaxies some of which are old, or will have stolen some stars from an old galaxy during a flyby. This story boils down to "at large scale stars are roughly evenly distributed".