And it's so complex that invoking something like a dark companion of the Sun (or indeed, the probably imaginary Oort Cloud) becomes superfluous. As Han Solo hollered, "don't give me the odds!" So many asteroids have turned out to be made up of two or more asteroids, the odds of a collision happening (which is akin to finding a needle in a haystack from a mile away, using another needle) appear to be, uh, not well understood. :^)
It may have been you who pointed me to this because I did more digging, but I found it interesting. :)
https://academic.oup.com/mnras/article/476/2/1624/4925565