Web Development – Does MVC Apply Only to Web?

I think you are looking at this in completely the wrong way. A GUI app and a web page are worlds apart so the exact same definition of MVC will never work for both. MVC is more about the ideal: separating certain parts of the app like display and logic.

In PHP (or the web in general), a View is the web page itself: the HTML output. It's not "live" as per your definition, but you simply click links to go back to the controller (i.e. another page request).

The Controller and Model is where things do differ, like you explained. In PHP the model tends to be the data layer, interacting with the database and so on. But it is still modelling the situation, and the controller still controls the application flow, if only once per page load.

So the name "Model-View-Controller" is perfectly logical, albeit a different implementation in GUI apps vs web apps.

Heh. Martin Fowler agrees with your confusion about MVC:

I don't find it terribly useful to think of MVC as a pattern because it contains quite a few different ideas. Different people reading about MVC in different places take different ideas from it and describe these as 'MVC'. If this doesn't cause enough confusion you then get the effect of misunderstandings of MVC that develop through a system of Chinese whispers.

However, he goes on to give one of the more cogent explanations of what motivates MVC:

At the heart of MVC is what I call Separated Presentation. The idea behind Separated Presentation is to make a clear division between domain objects that model our perception of the real world, and presentation objects that are the GUI elements we see on the screen. Domain objects should be completely self contained and work without reference to the presentation, they should also be able to support multiple presentations, possibly simultaneously.

You can read Fowler's entire article here.