After the helicopter of 1971, the system evolved to guarantee a safe rate, they went to fixing the ten year. This happened under Greenspan when we went to rate fixing, essentially a guarantee that 'pit slop' is one standard unit, not 1.5 standard units. Congress bnegan guaranteeing the sequence order o arrival. It became 'illegal' to time plot, and that means the single side Black-Sholes worked; no one knew howto do the double sided. Little brown people guaranteed Newton Episcopalian god became the law of the land.
Speculating on cause and effect
Black-Scholes got invented in response to leaving the gold standard. Then 30 years later we get QE, Roger Farmer and double sided option pricing. Roger discovers our death is a shorter sequence than our unpaid currency insurance debt. Hence, mathematicians corrected things.