As a product grows in popularity, it often becomes more complex, with the added features, functionality, and scale demanded by its expanding customer base. These changes may require rewriting or refactoring parts of the code before you can expand further, addressing what is usually called technology debt.
Such work is hidden entirely from the customer but may require a large percentage of the resources available for roadmap work. Some teams go quiet. Others create a technology roadmap or separate row on the product roadmap for this kind of work. How do you handle it? See Chapter 9 of my book, Product Roadmaps Relaunched.