I wrote:
"Obviously 100W is dissipated inthe transmitter and efficiency is 50%."

This is a Class A amplifier limit but not for other classes of
amplifiers. Terman tells us on page 450 of his 1955 opus:
"The high efficiency of the Class C amplifier is a result of the fact
that plate current is not allowed to flow except when the instantaneous
voltage drop across the tube is low; i.e., Eb supplies energy to the
amplifier only when the largest portion of this energy will be absorbed
by the tuned circuit.

"Transmission Lines, Antennas, and Wave Guides" by King, Mimno, and Wing
is an excellent reference, and like Terman, the authors agree with
Walter Maxwell. On page 43 is found:
"Principal of Conjugates in Impedance Matching - If a dissipationless
network is inserted between a constant-voltage generator of impedance Zg
and a load of impedance ZR such that maximum power is delivered to the
load, at every pair of terminals the impedance looking in opposite
directions are conjugates of each other."

The real world is full of imperfections which by no means preclude
practical work.

Best regards, Richard Harrison, KB5WZI