Right the operative word being good here, Almost all developers consider themselves good. Reality diverges from that point.
I always considered myself to be slightly above average developer. I have worked with a lot of smart guys some MIT alumni some self taught and among them I was average. It was not until, I ventured out into larger organizations that I got smacked with the reality of the passionless developer, that somehow learned enough to get a job but has no interest in technology other than it provides a fairly decent paycheck. I was stunned by this reality, up until this point I had worked in simulation, start-ups and small shops with really passionate guys who took pride in their code. When I first encountered the passionless developer I was appalled by their absolute disinterest in quality of code. Further many of them considered themselves to be senior and on par with the best of the best because their entire development existence has been in a sea of mediocrity.
True story, I remember when the shift started taking place for web apps. When the cool kids where starting to write the front-end in JavaScript and shooting off XHR request to the back end to get info and update the page dynamically, when they started dumping the bulky server side frameworks for more nimble and rapid client side toolkits.
I was at a fairly sizable organization and this stuff was by no means cutting edge anymore and I said you know, we should start doing some prototypes with this app architecture and see if it is advantageous. We already know that it produces a superior product in terms of usability so lets see if we can come up with a development process that is more efficient than we use now and give it a try. The response was well it's not Java and we are Java developers from a good deal of the team, the idea of not using a Java framework, to do web development, was hericy in their eyes.
I was floored, I had never identified myself as a (X) developer and the reality that people do smacked me in the face pretty hard. So the point is if someone is an (X) developer, chances are they are not as good as they think they are. Development is about applying technology to problems not applying technology (X) to problems. If a developer has already constructed that box around themselves it lends evidence to the fact that they might not posses the though process or creative thinking required to be a great developer.