"If I don't shoot him, someone else will" and that's a simplistic and morbid view of the situation. More often than we realize, others may pass as well.
Unfortunately, the simplistic view is often reality. We experienced that with a LARGE 3 year old with a nice 10 point rack last year that we were hoping would reach 4 or 5 and be a monster. Neighbor shot it and was so excited to see a decent buck he shot it poorly and lost it. Found it after the coyotes got it.