As soap operas set against the world of sex, drugs and rock 'n' roll go, "Daisy Jones & the Six" is a by-no-means groundbreaking but still-enjoyable account of the best band that never existed, charting its meteoric rise and just-as-abrupt fall. Credit that in part to the cast, starting with Riley Keough, who does her rock lineage and grandpa Elvis proud by belting out the group's songs.