The big bang did happen, but it was a natural explosion in the greater universe that broke the bounds of gravity, permanently freeing all the matter of the big bang from the original center of gravity, allowing seemingly endless expansion into open spaces. Whatever might have been in its way was pushed back or pulverised, except the largest black holes and galactic cores were moved much less but we're largely stripped of stars, and partially held their relative positions, and the galactic remnants became some of the drivers of galaxy formation in the new section of the universe. The force of the blast created a bubble within a pushed back section of the rest of the universe, and powered expansion for 9 billion years, but it waned as expansion continued, and now the gravitational pull from the rest of the universe has now become primary, and we've begun falling in all directions into the rest of the universe at an increased rate, faster at the outer edges as they get nearer.