FYI

The term "old time" was a creation of marketers.

In the 20's American recording companies realized that they could sell lots of records if they created them for specialized markets.

They needed labels for record bins. Thus, for example, was born the term "old time."

The target marker for "old time" music was southerners, transplanted southerners, or southerner-wannabes. It was called it "old time" to suggest that it came from an earlier, simpler, better age. The good old days, in other words.

Like "world music" today, the label "old time" included a dizzying array of repertoire, styles, arrangements, and instrumentation. The only thing the recordings had in common was the record bin and the target market.

My point. "Old time" has been from the beginning been an artificial construct. Looking for an "essence" is an exercise in futility.