Led Zeppelin – Physical Graffiti
With this example of Led Zeppelin you should start really understanding the huge lie in catalog album sales. In fact, Physical Graffiti hits are nowhere near as big as Toys In The Attic hits for example – Walk This Way has more streaming than all songs combined of the double album Physical Graffiti. If Led Zeppelin original album is on par sales-wise with Aerosmith set it is only thanks to the way Atlantic label decided to exploit the album by focusing mostly on the original albums rather than through compilations.
The main point to notice is that the oldest record on this list is from 1990, a huge 15 years after Physical Graffiti which thus faced no competition for a very long time.
All in all, Physical Graffiti songs, led by Kashmir, generated a relatively modest 2,7 million sales of subsequent full length records.