Your product must undergo major surgery sometimes. A refreshed UI or a new big feature touching critical parts of your app.
“We will ship altogether when it is ready” is usually how it goes. In those situations, it is very tempting to delay production releases. If you do that, you are increasing your following production release cost.
There are many ways to prevent it (feature flags, blue/green deployments); many are expensive to implement. Consistently increasing the QA coverage to a point where releasing new features to production is not risky is also costly.
What should you do then? Avoid major surgery. Big refactors and significant features put your app at risk. If you need to redesign the UI, fork the project. If you need to build a disruptive component, break it up, and release small chunks.