"art"
What provides resistance on the outside als skin depth can
by the reverse contain current flow to the inside.

This is another of your beliefs that not supported either by theory
or practice.

The word "tends" does not make the current passage
an undeniable fact.

I wrote "tends" because there is no discrete boundary near the outer surface
of a conductor where ALL of the alternating current flowing near its surface
is confined. But almost all of that current flows within several "skin
depths."

The 1.8 MHz skin depth in a round, copper conductor is about 0.06 mm, which
means that a tubular conductor with a wall thickness at least 3 times that
can be used in place of a solid conductor of the same outer diameter, with
no practical change in performance at that frequency.

RF