"Sander Vesik" wrote ...
But if you have two piles of rubble orbiting each other, then surely
tidal forces would over time convert these to fuzzy rubble-balls that would
then coalesce into a single body?

Over time they would become tidally locked to each other - and in the
process they would orbit further apart. (Or such is my back-of-cornflake-packet
understanding). Ignoring interactions with any _other_ bodies.