The practice forced landing is an entirely different exercise and was always designed to be carried out from various heights in the training area - and not as part of circuit training.
I realise it was different in ~1940 but in 2019 it is very difficult to legally practice a forced landing to the ground at/near metropolitan airports - impossible off airport and impossible from altitude on airport. Thus, despite your dogmatic pronouncements Centaurus, a glide approach is sometimes profitably used to practice the last part of the forced LANDING given the constraints that exist.
You also do a disservice when you say:
get the student to cut the throttle either abeam the downwind end of the runway or on the turn to base leg
The student should close the throttle at the point at which they judge the aeroplane, based on it's height, angle and distance from the runway, in the prevailing conditions can glide to a safe touch-down point and when to shorten the glide once assured to maximise the LDA. These are skills better learned when the exercise is permitted to continue to touchdown.
One reason glides aren't used routinely is you simply can't fit as many aeroplanes in the circuit if everyone is flying Auster/Tiger Moth style. Powered approaches also allow a greater margin for error, as you said yourself:
If you finish up high while attempting a glide approach and you already have landing flap down, then go around.
Well if you finish up high on a powered approach, you can reduce power and still effect a landing at the proper speed. Or you could even try sideslipping...
I can just imagine the chaos that would result at busy airports if you have every aeroplane gliding from close base until too low then adding power to fly level for a while then back to gliding until too high and going around? What would the '
let's do everything the same way as the FAA because some interpretations of their accident statistics show a lower accident rate or whatever without any regard to the scale, infrastructure and money in the industry there' zealots make of the
FAA Flying Handbook description of how to fly a 'normal' approach, and the benefits of a 'power off accuracy approach'?
What was the training accident rate in 1935?