I agree with you.
Programmer should at least know the basics and be able to write his own framework. Well, I haven’t developed my own framework and I use Zend Framework, but I learn the way it works, especially its MVC components and Tool framework so that I can develop my own extensions to it whenever needed.
Well, I don’t prefer to reinvent the wheel and keep using Zend Framework for production, but I want to be able to do it myself when needed.