ADDIE is more a process than a model. It is more about the what than the how.

In fact ADDIE simply tells what we have to do to create learning (or any other) content. How we do it will depend on time, resources and objectives.

While some will use it as a linear process, most will use it as an iterative process where they continually come back to previous stages to validate their work.

I think addie is still valid as long as we do not see it as a rigid linear model.