Well, if it's true the universe will start contracting at some point (which, some speculate, could happen sooner than we had thought[0]), and if a big crunch leads to a big bang, it is not impossible that this very moment - in the sense of these actual circumstances we're in - already happened an infinite number of times. (Still doesn't really answer the 'why?')

[0] https://www.independent.co.uk/space/universe-expanding-colla...