I agree with you, there is a time and a place. Disengaging to rtb for fuel or ammo, or disengaging because there are 3-10 of us on your butt is one thing, but I have single-handedly, on-my-own, away-from-anything, chased multiple aircraft that were supposed to be superior to mine all the way home.
Now, extending from me to maneuver is also a valid tactic. I've had plenty do that. They'll move out 1-2K then reverse and engage. Usually ends in decent fight (with me "learning" or dying, however you want to phrase it).
No, if a P-51 or LA-7 or Tempest or any of the other uber-craft run from a one-on-one from me in my spit9, everybody on 200 will hear about it.