The Product backlog never dries up

Over the last 2 months, I've closed a massive number of issues and PRs, and yet I'm still left with a long list of known issues. The backlog never seems to dry up, it just keeps piling up. The more I ship, the healthier the codebase gets, but the queue never really shrinks. I guess that's also a good thing in a way, it's what keeps the product improving and iterating. Would love to know if others are going through the same cycle.