Indie vs. Mainstream Cover Albums

Why do small Indie acts who aren't household release better cover albums than big name ones. I'm listening to the smartly produced Darrell Scott- Modern Hymns (Appleseed) release and at the same time looking at the track listing for a future James Taylor cover album. The differences are striking. Taylor's album, outside of a stray Dixie Chick song, sticks to the well-known, while Scott's, outside of a oft-covered Joni Mitchell and Paul Simon song, veers to the oddity. Indie acts aren't under the same pressure to sell records as a Rod Stewart, Barry Manilow or any other act under Clive Davis' wing. So when those people (or even a Country act like Martina McBride) go the cover route, labels want familiarity and sells. Indie acts take more chances in their selections.
Darrell Scott makes his money having his songs covered by Nashville mainstream artists. But he's also a recording artist, and his covers album has good obscure tracks written by Gordon Lightfoot, Hoyt Axton and Guy Clark to name some names you'll never see on a mainstream acts' album.
While some people cringe when an artist does a cover album, I usually enjoy them. But I want some weird choices mixed in with the old warhorses. Scott seems to feel the same way.