Apple has a long history of eliminating customization features within its operating systems:
1991 - Mac OS 7 (System 7) is released under Apple CEO John Sculley. The first Mac OS to support color, 7 allowed users to customize font highlight color, as well as window/scrollbar tint color. These features went largely unchanged through Systems 8 and 9.
1999 - Mac OS X (OS 10) is first major OS release under re-installed CEO and founder Steve Jobs. This time, no more window/scrollbar customization. All you get is cerulean blue or graphite. Jobs will no longer let a user's bad taste influence the perception of his products.
2007 - OS X Leopard eliminates the blue menubar Apple logo from the 'Blue' theme option. Graphite Apple-only now.
2013 - There is basically only one dynamic background pre-loaded into iOS 7. The bright one is meant for the lock screen, with no icons or UI elements to clash with. This is the ideal. Jony Ive intended it to scream "this is iOS 7!". The muted version is for the home screen, somewhat neutralized because it must actually function as a background. Although I strongly suspect Jony has the bright one on both screens.
1991 - Mac OS 7 (System 7) is released under Apple CEO John Sculley. The first Mac OS to support color, 7 allowed users to customize font highlight color, as well as window/scrollbar tint color. These features went largely unchanged through Systems 8 and 9.
1999 - Mac OS X (OS 10) is first major OS release under re-installed CEO and founder Steve Jobs. This time, no more window/scrollbar customization. All you get is cerulean blue or graphite. Jobs will no longer let a user's bad taste influence the perception of his products.
2007 - OS X Leopard eliminates the blue menubar Apple logo from the 'Blue' theme option. Graphite Apple-only now.
2013 - There is basically only one dynamic background pre-loaded into iOS 7. The bright one is meant for the lock screen, with no icons or UI elements to clash with. This is the ideal. Jony Ive intended it to scream "this is iOS 7!". The muted version is for the home screen, somewhat neutralized because it must actually function as a background. Although I strongly suspect Jony has the bright one on both screens.