A team spends a sprint optimizing LCP. Numbers improve. Six months later the app is slower than before the work started. Nobody made a single decision to make it slower. It just accumulated. This is the normal trajectory without structural changes. Individual optimizations decay. Culture doesn't. Why the gains disappear Performance degrades through ordinary work. A developer adds a new dependency. A designer hands off a 1.4MB hero image and nobody checks the size. Marketing adds a tag via the tag manager. A component gets a useEffect with a missing dependency that triggers extra renders. Each change is small, reviewed individually, and ships fine. The problem is that performance review doesn't happen at the same granularity as code review. Code gets scrutinized line by line. Performance gets checked periodically, if at all, by whoever remembers to run Lighthouse.…