Simple question, or is it...

The signal is not the Poynting vectors. The direction of the Poynting vectors are not even in the direction of the current. You know what a vector is, right? We’ve already covered all that. Come on, guys. Wake up and smell the coffee! ☕️ Stop trying to cherry pick 🍒 Wikipedia. Photons have no problem traveling through solid material like say, glass and water. That’s pretty obvious. Especially for high energy photons.

Electrical energy delivered to the load is flowing entirely through the dielectric between the conductors.

Very little energy flows in the conductors themselves,

Stay on point.....

It’s you who can’t keep it straight. The signal is not the Poynting vectors. 

I don't think anyone uses transmission lines for interconnects or speaker cables.