I am a Hamilton fan and have been since he was in F2 (GP2 back then) and am just as chuffed as all his other Fans at his achievement, and I would certainly say he is G.O.H.T. (Greatest of His Time) but G.O.A.T is a difficult if not impossible target for any one. He is racing in different equipment on different tracks with greatly improved safety.
I don't miss the days when F1 life expectancy was short but how many of the drivers who died young would have been able to do what Hamilton has achieved if they had raced in this generation and lived to achieve more?
Back in those days you "Quit whist you were ahead" nobody has sufficient death wish to push on too far and no body had a chance to drive until they were too old to drive.