luckily the heat of components inside the PC was lower in the age of IDE and flat cables that didn't care what you wanted with airflow.
I learned about benefits of airflow by accident through using my last 2 cases. My
TJ09 had an extra fan in front of GPU that sucked air in through vents on sides whereas my
FT02 showed me benefits of positive pressure by having what was until this year the best air cooling in any case for last 10 years.
Cases caring to give you places to put cables only started in the last 10 years, any case before then it was not even thought of. Its now expected whereas I expect early on you paid for the privilege. My current case only one I have had that had any.