@sir Alternative theory:
Programmers work for companies. Companies have business goals. Companies want programmers to achieve those goals as fast as possible. Programmers internalized this into a stockholm-syndromish sense of "professionalism" that's defined as achieving business goals as efficiently as possible.
Business goals trump performance. Performance only affects business goals if it impacts sales. So programs are written to work as slowly and be as shitty, as business can get away with.