De facto,
Deciding on a Go-around at 50ft in a B777-3 when you had the choice to do it earlier puts you at very high risk of striking the tail and therefore very poor judgement ! At that height even with a perfectly executed G/A the gear will likely strike the runway leaving as little as 8 degrees pitch to tail strike. You have to be incredibly careful but that comes with knowing your aeroplane. Delaying the decision until 50ft is not on with aircraft of this size. They will punish "push-on-itis" severely. I'll leave that kind of thinking to guys flying puddle jumpers !