and commercialization wasnt done until the like 1994. OSI as a successor was still proposed when the first BGP4 rfc came out.
before commercialization happened, IP was mostly the realm of government and education.
I feel like your experience was quite different to mine. I used TCP/IP in the late 80s at university and doing commercial contract work. I remember OSI existing but at the places I worked it was treated as less common.