> Someone should be able to freeze their user interface in time if they wish.

Why?

Because people are habitual, and mental load increases when you have to learn the UI again every update. Like if someone decided to change all your pots and pans every few months, it's harzadous for cooking.

For the same reason you can keep the interior design of your house the same for decades. Also, why not? It should just be a UI theme, decoupled from actual functionality.