Perhaps there are/have been billions of universes (but where did they come from?). Perhaps the laws of physics are different in each and where a universe works properly life will arise to ask these questions. Perhaps the current universe is part of a single sequence of universes that gradually settle towards the ideal laws of physics (but where did it come from?). Perhaps the universe was designed by an intelligence (but who designed them?). Perhaps multi-dimensional membranes clash together and form universes (but where did the 'branes come from?).

The "what is the mechanism behind it?" question just gets moved backwards.