Why are we here on earth???
There is actually a lot of serious discoveries lead by the big bang theory, on how the universe started to form as it was expanding. There are quite a few very interesting facts that show a delicate balance between what it is and what could have been (or not being at all) if several key events and ingredients (sort of speak) would have been just slightly different and that open a lot of questions for speculation just like the one that you have posed. The best answer I can offer for you is that what we know today is better than yesterday and science will keep working to make sure that what we will know tomorrow will be better than today....until the end of time