[hbosch]

In my experience, the "why" is more often called by a manager, director, or VP who wants a big project under their belt. The amount of times a "major design change" has happened from the bottom-up is very, very, almost impossibly rare in most cases. Sad story, but a true story.

[firecall]

This is correct.

Management gets bored.

Source: Me, previously a Big Brand Marketing Manager

[strunz]

Not bored as much as "I need a big project to parlay into a VP/Executive role"