die a slow death

To fail or become irrelevant in small increments over time. The athletic event used to draw huge numbers of spectators, but with attendance dwindling every year, it seems to be dying a slow death. Many are wondering if the once-mighty social media platform might be dying a slow death, as other competitors have skyrocketed past it in public perception. That show's first two seasons were great, but it began to die a slow death once the head writer left.