Firstly, I think most people who actually listen to music (rather than simply have it on in the background) would hear the difference between different chord inversions, although they might not be able to put their finger on what makes the difference. You seem to be suggesting that it doesn't matter what the guitarist plays as long as they keep in time.

"Even the basic chord isn't usually very important". I'm not sure what you mean by that. If it's the wrong chord it's very important. What chord is wrong or right is another matter - folk tunes are often ambiguous in terms of keys and scales, and there may be several possible chords which work equally well - it can come down to personal taste.

What I agree with is that the tunes aren't driven by chord progressions. You have to fit the chords to the tune rather than follow a progression laid down by musical theory.