In folk music, there's really no such thing as "correct" or "wrong"- there's only "successful" (it gets played) and "unsuccessful" (shut the f* up). So if you want to play a reel as a slip jig, go ahead, but it's up to the community- other musicians- to decide whether it works or not.

It's worth looking at any self- organising system in evolutionary terms, and drawing comparisons from biology.

Often a popular recording will, like a commercial apple, all but wipe out all other variants of the same song/ tune- I remember Derek Elliot complaining bitterly that folk club audiences all joined in one of his songs with the chorus as sung by Martin Carthy.

And some tunes flourish like Japanese Knotweed- the Ashokan Farewell being one.