Web development seems to be trending towards full client-side MVC application frameworks, not unlike those used by native developers. It leaves me wondering wha

Web development seems to be trending towards full client-side MVC application frameworks, not unlike those used by native developers. It leaves me wondering what the browser really brings to the table? As we are reaching the point where the browser is a poor mans virtual machine and nothing more, why not just provide a virtual machine and let HTML be just another application on the virtual machine?