When is obsolete, obsolete?

Recently, the subject of when a part becomes obsolete came up… and I had to explain my answer of … it depends on your perspective … as:

 A manufacturer might consider the item obsolete when they no longer make it

 A buyer might consider the item obsolete even later when they cannot but it – from the OEM or 3^rd party providers

 A supply chain might consider the item obsolete even later when it is no longer held in their warehouses.

 An equipment team’s engineers and maintainers might consider the item obsolete even later when it is no longer installed on any supported equipment asset

 the user organization might the item obsolete even later when the data associated with the item is no longer of interest.

Many organizations and software applications use the 1^st three perspectives and neglect the often much later obsolescence moments. What’s your thoughts on these perspectives of obsolescence? Did we miss any? Have you seen issues where these perspectives were ignored?