The interaction model is something that users internalize, but probably could not articulate, and would not care whether they could. Users internalize well-constructed interaction models, which make most actions within a system more predictable. We usually do not notice a product or application when it works well. There is no ultimate solution for the web interaction model.
Every product solves a different set of problems for different users, and therefore, requires a model that, as much as possible, reflects and supports their real-world interactions. If they are designing a simple Web portal, they may be right. However, any time a product needs to scale to support complex interactions or comprises more than a dozen pages or so, its designers need to step back and define its interaction model first.