Do you suppose everything is explainable? Gravity feels to me like the sort of thing that just sort of is. I'm all for better characterizations of it, but I'm not holding my breath for an answer to: why?
How does our biology affect the limits of what we can comprehend?
But here I am in this body, and not that one, so I'm content to accept an axiom or two.
I'm not proposing that gravity is underpinned by something complex, just that if its mechanism is out of our reach then so to are any conclusions about that mechanism's complexity.