This is a fine collection of classic performances of stone American folksongs. I heard some of these recordings growing up in the 1960s, though more from my mother's singing to me as a child. As she was not especially musical, nor a record-buyer or folkie, this seems pretty good evidence many had entered into the broader folksong pantheon by then.
I don't understand the comment that it isn't real folk music - it seems pretty archetypally American folk to me: if "Aunt Rhody", "Ezekiel", "John Hardy", Bluetail Fly", "Froggy" etc aren't folk music, what is? - but maybe the reviewer is new to American folk. It's true that some have British Isles roots, but that hardly disqualifies them either as folk or as American songs - all folksongs come from somewhere, and are transformed by performance in time, place and social context. Similarly, for the idea that royalty payments influenced the choice - if the Q is, why these 10 performers instead of others? Yes, they were all popular and commercial at times - though also just scraped by at times, or were literally hounded out of the music business and blacklisted at others - I assume the idea is to give a picture of the folk music that was created and recreated for a broad audience in a modern idiom, within the limits of licensing constraints. Even the Leadbelly recordings are commercial ones - this isn't John and Alan Lomax's amateurs in field, hollow or prison. In fact, these musicians all knew each other and often performed together, so uniting them in a collection has the virtue of coherence.
Not everything will be to everyone's taste - I never cared for Burl Ives that much, though listening to him now I respect it more than when seeing him endlessly on 1970s TV shows. Other people did "Rising Sun" better than Woody, and why not Marty Robbins on "Streets of Laredo", or a true bluegrass artist on "Muleskinner" or "Old Dan Tucker"?, etc etc. But there are a good number of absolute classics here, and nearly everyone will find some fascinating discoveries. The idea that you could do better than this for a few pounds is either shocking, or reminds me of $2 used two-fers back in my adolescence...
In short, I loved it.