Genghis
A lot of jets pitch down too
But going back to the original question you pitch for potential energy from the airframe which has to mean a loss of altitude to get that energy and you power for energy from the engine.
In my minds eye elevator and throttle are both connected to an energy source which is available to the pilot.
In some situations you need more from one less from the other or max from both.
So both pitch for speed or power for speed are false statements unless you happen to be a glider pitching for speed.
I think it is misleading to not train pilots to use all the controls and energy sources available to them.
Using one method is false training although I fully understand pitching for speed with students in low powered aircraft but it is still incomplete training.
Pace