"In essence, if your aircraft glides at a steeper angle than its climb angle and you try a 180 you are NOT going to make it."
This is probably the most elegant anti-turnback argument I've ever read, because it is irrefutable."
Hmm; climb angle, best-rate, best-angle, glide for range, glide for duration. So much more complex than that Dave, and you don't appear to be considering the 'excess energy' at the point of engine failure, i.e. adding speed to height during the start of the glide (i.e. the engine stops)!
Most military hardware is taking-off and accelerating to an airspeed somewhat higher than the best-range glide speed.