I believe the answer to your question of why developers don't generally treat quality the way dentists do is one of economics. The world needs enough software,

I believe the answer to your question of why developers don't generally treat quality the way dentists do is one of economics. The world needs enough software, and the world's requirements for quality are low enough, and the average developer writes reliable-enough code, that in most cases money can be made without special attention to quality. In some domains, quality is paramount. I imagine that quality and bug mitigation are the primary concerns of someone who manages, say, an X-ray machine firmware project, or avionics software. Software for these purposes that is not extremely reliable cannot compete in that market. For other kinds of software people are paid to write -- like social networks for pets -- reliability is a much lower priority. Certain kinds of software needs to be rewritten constantly to meet the demands of highly-evolving markets. Games are an example of this. Reliability is important, but not paramount, because the underlying business can only continue to compete by at some point stopping work on the reliability of existing games, and moving on to developing new games. I'm sympathetic to the respect you have for the value of high quality software. But the reality is, the value of quality varies dramatically within the software industry -- much more than it does within, say, dentistry, or medicine, or aviation. Fewer bugs isn't necessarily the primary concern of those using and buying any particular kind of software.