Confused about variables

Does all this mean that what are often called variables when referring to controllers are actually just statics, and are more akin to constants given that the controller and everything associated with it are destroyed once the view is rendered and served out to the user?

While it is true that everything associated with the controller are destroyed once the view is rendered and served out variables are well... variable. They exist while the script is executing and can be assigned new values. Constants cannot be assigned new values once defined.

In PHP a static variable relates to variable scoping. Static variables exist only in a local function scope, but it does not lose its value when program execution leaves this scope. The must be explicitly declared as static ie. static $count = 0;

I suppose that class properties that are variables might be considered static in that they maintain an assigned value for the lifetime of the class - except they never go out of scope in the context of the class.