The wires appear to enter the lamppost about 2 or more feet down.
Light excavation around the lamppost got me down to a plug of concrete.
I would have to go lots deeper (and beyond the concrete) to get to the
place where the wires enter the lamp post. Easier to take the wires at
the top, where they enter the lamp. Can't find a junction box on the
outside of the house.

Is an electrician going to want to dig out an old lamp post?