JS, while I thoroughly support the general thrust of this argument I thought it worthwhile making a couple of observations:
You often comment on "(only) a 1500hr PPL". 1500hrs in anyone's book is a reasonable amount of hours. Equally, there are many PPLs out there who are exceptional pilots. Yes, I see the link you are trying to make with commercial activity but this is rather tenuous; in the UK, at least, a PPL can fly for charity work.
Back seat driver - the Stearman, like many early taildraggers, is primarily driven from the back seat. Sure, it's nice having highly qualified help up front but one would expect the aircraft commander to be sat in the back.
I'm not trying to undermine your argument, I'm just trying to identify the chinks in your armour.