So, some metaphysical relevation:
It appears there really isn't a satisfactory solution to the question of why
Consider this. We have so much particle phenomenology to probe quantum field theory
Using the experiment results, we refined the underlying mathematical models of QFT
Usually, that means new symmetries get introduced, and some old rules get tidied up
But if we pause and think of all of this for a second...
Under metaphysics and pataphysics, every single thing are in a sense, unique and also things
That means, at the ground level, there really is no difference between e.g. spacetime, particles, mathematics etc. when you bin them in terms of philosophical categories
But with that, it means all our particle physics experiments are really doing one thing: Mapping out the QFT landscape
So say many years later, we have a reasonably good model that explains most things (and hopefully by then quantum gravity is solved). But then that still left behind a "why" question:
Why do the QFT landscape have the structures and symmetries it does. Or rather, why do our models with these structures corresponds to how reality interacts with our models via experiments
Sure, one can say "God does it", "the multiverse", "it causes itself" etc. and all that
But in the end, that is only pushing the "why" even further back
Thus it seems, all the question of "whys" are really this following root question:
> Why do things have the structure they do, regardless of how high in physics or metaphysics you go
> and is there really an answer to this root Why question
which ultimately boils down to the following:
> Why does existence itself exists?