Some day we might just re-crack the illusive code to incredible, unbelievable numbers. Keep building, boys.
We already know the code, folks have just been scared off by the "save your bow from breakdown" fear mongering.
Back then guys shot them out and made another. The odd thing is that the people most into saving their bows from stress probably make and discard/retire more bows than anyone else.
Sleek, The bow Stevenson shot over 300 with was a heavyish draw Yew recurve. Likely of somewhat shorter length and probably overdrawn too. He liked heavy draw weight and heavier arrows but undoubtedly the arrow was still less than 10gpp.