That’s a tough call to make after the fact. I can’t remember ever really finishing a TT and not feeling like I couldn’t have gone harder somewhere. Similarly with workouts, if I’ve ever had to bail out I always think afterwards I should have just somehow managed for complete it but the reality is I couldn’t have gone harder or faster because otherwise I would have. At that moment in time that’s all I was good for.
That I think is nearer the truth (for me anyway). If I give up on an interval knowing at that moment in time I could carry on if I absolutely had to then I haven’t hit the goal.