My take on the 4 corner offense -
First off, I am a former college player from that era (mid 70's). Our coach was a Dean Smith disciple. You have to remember there was no shot clock, but more importantly, no 3 point line. It was less important at that time for the defense to have to extend themselves out to guard long range shooters. Defenses could just clog up the middle, and if a guy hits a 22 footer, so be it. It was still only 2 points.
We had good teams, but not a lot of pure shooters. We were at our best when running a pick & roll, motion type offense. It was hard to do against a packed-in zone. We wanted to force them into playing man to man defense and spread out the floor, which played to our strength. One of the rules in college basketball at that time (which no longer exists because of the shot clock), was that the team that was behind on the scoreboard must initiate play, and if the game was tied, the defense must initiate play. If the team with the ball was tied or ahead, they could go into the 4 corners to spread the court and force the defense to come out and guard them. If they didn't, the official would give a warning to the coach to make his team go out and defend. If after a few seconds they still didn't do it, a technical was called.
Now remember, you could only run the 4 corners if you were tied or ahead in the game (as North Carolina usually was). It was not really meant to slow down the game, in fact, it was more to speed up play and force the other team to play at a faster pace by making them come out of their packed-in zones and spread the floor to create more movement and motion.
Hope I explained it so it makes sense.