I wouldn't say the Corries revived Scottish music.. but they rode on the back of a folk revival.   The peak of Scottish Heather n' hills music as a national family viewing and listening thing, was late 50's-80's.. and apart from theatre shows, there were plenty of TV shows.. with Tenors, Accordion Players, Folk Singers, and statutory dancers.   also loads of radio shows.   Kennedy, Alexander Bros., McKellar Tartan Lads, Andy Stewart, Joe Gordon, Folk Groups galore.. They were at the popular end of that. Like all booms there is an end, it eventually looked jaded, and gradually the main media altered the type of Scottish trad. they put on TV and radio. Also the main London record labels, like Decca, Pye, EMI etc. who made stars of many names in that period, were no longer actively involved with that type of act.. and Runrig, Proclaimers etc. took over and had their turn in the popularity stakes.