Bob: a very interesting look at the question. I'm 90% in agreement, though not totally happy about your equating folk with what one solo person can deliver. The village band has a long and distinguished history servicing births, marriages, deaths, seasonal celebrations, pissup etc. and long may it continue to do so.
But your general point seems spot on. The revival used (and to a lesser extent uses) folk material, but is not itself part of any folk tradition. Except in so far as some genuinely trad folk msucians got into the revival, whether for enjoyment or employment. But the current folk revival has as much, or as little, to with folk as Benjamin Britten, Vaughan Williams and those others revivers before. They came, admired, borrowed, rearranged, wrote songs in the style of: but they never joined, and never really could join.The Gates of Eden only opened to let people out.
That may not be the case with the next revival, of course. It will depend on the people involved. But the current revival merely created its own scene.