First of all, the MVC patterns/ architecture says nothing about classes in particular at all. This is obviously another one of your misunderstandings or twisting of facts to fit your prerogatives.
Secondly, you need more than three classes, because a view, or a controller or a model aren’t singular responsibilities, but rather main concerns within the application’s architecture. To me, overall, the MVC pattern is the main behavior an MVC framework offers. Each one of the 3 MVC concerns also have a good number of objects and tasks needed to achieve the goals of the framework and the application. These objects and tasks are the responsibilities.
It looks like you are mixing up the concerns of MVC and understanding them as single responsibilities. This is why your framework is missing out on class fidelity ( a term I just coined myself).
class fidelity - when an experienced programmer new to an application can relatively easily determine the single responsibilities of classes.