I am not sure if this is the origin, but all [Viennese Waltzes](https://youtu.be/wkzlv90zZxg?si=QzagvsRiwosM9P0R) are in 6/8, and the lead is dancing: LEFT right together, Right left together.
There is a heavily implied ONE (2 3), TWO (2 3) whereas for slow waltzes in 3/4 the beats/steps are a bit more evenly enunciated, and the phrasing stretches over two measures.
As popular music is built around human movement and expression, and humans have two feet, you get this norm. Deviations and syncopation can be used for effect, but are the exceptions that prove the rule.
Latest Answers