‘Fallout’ isn’t just ‘derived from’, it’s a direct descendant of ‘Wasteland’, with some of the same people involved: Brian Fargo was the director on the original ‘Wasteland’, then founded Interplay aka the developer/publisher of ‘Fallout’ 1-2, and shortly thereafter inXile Entertainment that later developed ‘Wasteland’ 2 and 3.

Also, some of the folks who developed ‘Fallout’ made ‘Arcanum: Of Steamworks and Magick Obscura’, which is basically fantasy ‘Fallout’ — made by folks of Troika Games who previously made ‘Fallout’, and later ‘Vampire: The Masquerade – Bloodlines’.