For those that didn't click through, I believe the parent is demonstrating that it is a best practice to have many clusters for a variety of reasons such as: "Create one cluster per project to reduce the risk of project-level configurations"

For robust configuration yes. However one can certainly collapse/shrink if having multiple clusters is going to be a burden cost-wise and operation-wise. This best practices was modeled based on the most robust architecture.

This is it exactly.

Thank you.