It is hard to estimate the age of a black hole just a few tens of billions of years old. Yes, it is possible that our Big Bang could have created multiple black holes, and that is one acceptable solution to the presence of black holes in ancient galaxies such as the MW. Still, the original suggestion remains viable.<br /><br />I might also add that space-time AS WE KNOW IT is OUR space and OUR time. Black holes could transit/persist from one space-time continuum to another. Nobody has conclusively proven that ALL of a previous universe must have collected at precisely one point at precisely one time to suffice for a Big Bang to occur. Perhaps there is a critical mass for Big Bang events to occur, beyond even supermassive black holes, but certainly much less than the total mass of a "universe." Here is an interesting physics problem, analogous to what it takes for a white dwarf to become a Type I supernova, but of course on a different scale. The difference is we can see and measure supernovas, but not yet Big Bangs. Our space-time universe is thus both a womb and an observational tomb -- unless studies of gravitons and other exotica phenomena point to possible interpenetration among adjacent universes.<br />