That view of the development process is a bit reductive, I'm not sure the dev working on fixing a regression on some crusty, old, ugly, but contractually maintained branch of the product considers itself to be a big shot. But that's where most of the money comes from, so that's where this function has to act. Maintenance caused by unprovoked changes is not the lot of any single person or job in the company, it is in fact probably the most common facet of any tech job.