So, is the OP right?
Yes, this video explains it pretty well: https://www.youtube.com/watch?v=mjYjFEp9Yx0
Essentially, since the scan rate of NTSC is 59.94 fields per second, there are 29.97 “frames” per second (one field is half of a frame). Film to video transfers were done using a process known as a 2:3 pull-down which separates 4 film frames amongst 10 fields (5 frames). The resulting perceived frame-rate is 23.976 fps since 4/5 = 23.976/29.97. Overall 23.976 fps is merely a consequence of video technology and nothing to do with a film cameras inability to maintain a constant 24 fps. What I am not sure about however is why keep it around even when modern equipment can shoot and project at exactly 24 fps?