Experienced programmers know how fundamental good systems architecture is and always model
their systems based on good Systems Design practices.
However, most of the time these programmers will implement architecture which they are comfortable with, and this specific architecture is not necessarily standardized, meaning other programmers might find it hard to understand the software.
MVC (Model View Controller) solves this phenomena, as its a standardized architecture and method for developing software. We've had MVC frameworks for some time now, to the likes of Zend Framework, CakePHP, CodeIgniter, Symfony etc.
Applying for a Web development position these days you'll find more than often that MVC and popular frameworks like Zend Framework, Symfony etc. to be a requirement.
I believe we're in a new era of web development, were many practices are standardized on a more global scale and The Zend Company / Zend Framework has definitely contributed to this, which has long been awaited!