The fact that scoring was higher in the 1970s, 80s and 90s was seen on national teams: They were loaded with great shooters. That and they almost all used wide-open offenses: stretching the defense with the fast break; spreading the defense with spacing and movement.
I coached Chile for two years, 1971-73, and I had three smaller guys in the starting lineup because they were great shooters: 5'9" Lorenzo Pardo; 5'10" Manuel Herrera; 5'11" Edgardo Arismendi. I also had people coming off the bench that could shoot: 6'4" Oscar Fornoni; 6'0" José Verdejo; 6'6" Carlos Zarges. No advantage because every other coach had figured out he needed shooters, as well.
The emphasis was on offense. You did not want to play a zone defense back then because they shot those out of the water in no time with deadly 'spot' shooting and 'skip' passes. No team in the 1973 Worlds or 1973 South Americans played zone defense. Yes, they played defense: physical man-to-man defense. Ask anyone that faced the USSR or Yugoslavia back then if they played defense. Their scorers, aware of physical defense, knew how to get hit in mid-air and still make the drive or the jump shot. The idea was not to 'run an offense' but, rather, to 'attack.' There was no 3-point shot back then, so they used every square inch of the shooting area for pickup Js or catch-and-shoot.
In the 1973 South Americans, we faced Brazil. They were simply loaded with long-range shooters: Helio Rubens, Ze Geraldo, Carioquinho, Mosquito, Adilson. We faced Argentina, and its shooters: Raùl Guitart, Fernando Prato, Roberto Palladini, Alberto Cabrera, Carlos Raffaelli, Eduardo Cadillac, Carlos Gonzalez. Peru had Eduardo Airaldi, Jr. Colombia had Jairo Romero. Uruguay had Sergio Pisano, Victor Hernandez and Daniel Borroni. We did not face Cuba in the 1973 Worlds, but they had Frank Standard, Ruperto Herrera, Tomàs Herrera, and Rafael Canizares. We're talking about shooters that were death from downtown.