Old music like Queen and The Beatles is seen in some’s eyes as the only real form of music. Bands like One Direction aren’t seen as “real bands” because they’re deemed as too bubblegum pop. We will always label music as good or bad, when in reality there probably is no such thing as “bad music.”
Licensing all that music in the late ’90s or early aughts would have been cost-prohibitive, but in this day and age where revenue streams have totally changed (most bands don’t make much money off their album sales anymore), so has the structure of music licensing. In short, it’s rather inexpensive these days and by the looks of the soundtrack details that have arrived today.