Certainly not. While website builders are getting much better creating the HTML/CSS yourself is much better in everyway. The main one is creating it yourself ensures your website looks the same in all the browsers and doesn't contain unnecessary code that could cause you problems in the future. Also these website builders create the HTML/CSS for you they can never replace it because every website is made up of HTML.
I definitely agree with sequencehosting. Many of the automatic website makers are horrible when wanting minimal source code and image size. Even if you have two identical websites, say one made by a generator and one by myself, chances are that mine shall loads faster and not affect bandwidth as much. One huge advantage by having a developer make a page is the fact that there are a lot more ways a person can think of something than a program with a predefined set of functions.