Sorry to disagree Howard, but as far as the general population is concerned, there is no "wider meaning".

Sorry Jim but I stick with it. I agree most people don't give folk music a thought from one week to the next, but most have a vague notion what it means, and it is only the wider meaning. Their idea will probably include some old farm labourer in a pub, and a group playing diddly-diddly, but it will also include Dylan, Simon and Garfunkle, and probably Rambling Sid Rumpo. It's a fuzzy idea, rather than a definition, but I think it's fairly widely understood.

What they don't have is an understanding of the difference between what you regard as 'folk' and the other stuff, far less the importance of that.

If "most people" didn't have this wider understanding of the word, your complaint that it devalues the real meaning of 'folk' wouldn't matter. It's precisely because it is so widespread that the damage you fear might occur. However you cannot alter the way language is used, especially when that use has been well-established for more than half a century.