BOAC, your ‘surety’ assumption about Boeing’s addition might be the weakness of your argument. However, I would accept that whatever a manufacturer publishes is normally based on sound reasoning.
An exception to the reasoned argument might be found in the FSF stabilised approach criteria (< Vref + 20). Most manufacturers preferred Vref+15, but Boeing’s argument that Vref+20 was already in their books won the day (he who pays the piper).
You could argue the probability of having a heavy landing vs a rough overrun; but my earlier question was if the industry has any recent atmospheric data to help validate procedures and additions based on the likely wind change (what is the extent of the threat), or if modern aircraft might be more resilient to wind shears and gusts during landing.