Will machines completely replace all human beings?

In very meaningful cases machines already have control, and armies are not unnecessary. So we can extrapolate that armies will probably also not be unnecessary in the future.

The purpose / goal / sense of life could be to fulfill / accomplish / achieve what was set in the beginning of it.

Provided that the purpose / goal / sense of technical beings is similar to the purpose / goal / sense of living beings, then we probably have to determine: In the beginning of the technical beings the replacement of those beings who created them was set, and when the replacement will be fulfilled / accomplished / achieved, then, simultaneously, the machines will either have destroyed themselves or created another being with another purpose / goal / sense.