The Nitty Gritty Dirt Band re-introduced Doc Watson? Since when did Doc Watson need re-introducing? I don't believe his populariy ever wained but has just constantly grown ever since Ralph Rinzler via Tom "Clarence" Ashley brought him to our attention.
The Dirt Band albums may have spread knowledge of this fine music to a wider audience but Re-Introducing is the wrong word.

Hoot - in nit-picking mode