It rather depends. There are branches of physics (m-branes, multi-universe, some offshoots of string theory) that could possibly have answers to this, should they figure out ways to test and measure such things. They are somewhere in the realm of philosophy or mathematical conjecture until that point though.

And potentially that pushes the question back further - so where did all that come from?

I took issue with the initial post because it sounded conspiratorial, and it also sounded like there was a huge cop-out at the centrw of everything that people were trying to ignore. On the contrary - it's very interesting and it's no shame or revelation to say "we don't know yet, and we don't know if we ever will"