Why agile always fail within a waterfall structure?

Alot of development teams have tried introducing agile from the grass root level, and failed. Why? Because most team tries to hide agile within a waterfall structure.

Agile and waterfall are two very different approach. Having an agile process within a waterfall fixed budget timeline is bound to fail. Agile is about embracing change, while the other tries to reduce, minimize change.

Having agile within a waterfall structure will introduce nothing but scope creep.