Roger Long related thusly:
The primary thing keeping air traffic straightened out where there is
no ATC or tower is everyone following right of way rules and behaving
in a predictable fashion. The radio is a secondary back up. As soon
as pilots start using the radio as the primary tool, relying on it
rather than proper behavior, things get hairy.

And at uncontrolled airports you can also have aircraft taking off or
entering the traffic flow to land that do not have a radio (I haven't
flown in some years, is this still possible with the new rules?). So
"predictable" behavior allows everyone to mesh safely in the pattern at
relatively (to boats) high speed, regardless of radio communication.
Predictable air traffic behavior is a primary result of the rules, just
like on the water. It is when we encounter someone who does not know, or
who does not follow the rules that we have those hairy situations. Then
it is our responsibility to avoid them.

I handled it properly and differently than
you might have but THAT'S NOT THE DAMN POINT!

Yeah, well it might not have been your point that you handled it
properly, but its still a valid point. If the other guy ain't gonna move
to avoid a collision, then you have to - and in time, which you did.