re: Why ?
Why the why ?
Dangerous question because :
We don't know enough to be able to have a convincing answer.
When we deal with the big bang, it might not even be the way it all began!
But when we go for an answer, then we are most certainly wrong.
Frankly, I prefer to admit not knowing than to want an answer (which will more reveal about myself than about what there is).
When one googles on the question, one finds more religious sites than scientific sites (ouch !!!); this alone, tells more about the problem.
Because it is what we see!!! And we have to go from there, reverse engineer what we see evolving to the future...But we won't go all the way.