Jim Kelley wrote:
"That`s because power doesn`t propagate, and hasten to add - neither do
Poynting vectots."

One could make a long list of serious authors who freely treat power as
moving energy. I namrd Ktaus, Ridenour, Purcell, and Walter Maxwell.

Terman was another world-class expert who was unafraid of the word
"power". On page 76 of his 1955 edition he wrote:
"Alternatively, a load impedance may be matched to a source of power in
such a way as to make the power delivered to the load a maximum (The
power delivered to the load under these conditions is termed the
available power of the power source). This is accomplished by making the
load impedance the conjugate of the generator impedance as defined by
Thevenin`s theorem. That is, the load impedance must have the same
magnitude as the generator impedance, but the phase angle of the load is
the negative of the phase angle of the generator impedance."

I have not yet seen a copy of "Reflections", but would bet that W2DU
says the same thing, perhaps in fewer and shorter words.

Best regards, Richard Harrison, KB5WZI