When you do the numbers and they give you an answer, you don't dismiss it as "absurd".

One man's modus ponens is another man's modus tollens. You have amply explained why you reached the conclusion you did based on idiosyncratic personal preferences and constructed an unconvincing model to try to justify it; there are no 'numbers' here, there is only absurd reference class tennis. ('Stratford-on-Avon had 0.0001% of the medieval English population; the odds against the greatest English writer coming from Stratford-on-Avon is astronomically unlikely!') I am perfectly happy saying that the result refute the pseudo-premises - not that you gave a precise model in the first place: I will ask you again, what is the right amount of criticism for Shakespeare that would satisfy you that he really was the greatest writer ever?

My separation of classes chronologically is, like all good models, inspired by observation. In this case, the observation that a statistically-impossible number of the people considered "best in field" came very early in those fields, even in fields like literature where coming early is a disadvantage rather than an advantage as regards the quality or contemporary opinion of your work.

The damning point here is that you are willing to bite the bullet and say it applies to sciences as well, where we would, contrariwise, naturally expect the earlier a scientist to live, the easier it is to make incredible discoveries and pick up low-hanging fruit. Only an early scientists has a hope of discovering, say, gravity. Or an early mathematician something like calculus. You have to live as early as Parmenides if you want to discover something basic and extremely important like 'the moon is illuminated by the sun'.