Most people have never worked on a long term project applying SOLID principles and DDD and therefore cannot fathom how efficient a team can be when it is applied.

Have you ever worked at a company where you join and there is a God class (or two or three) and none of the business people and developers talk the same language. The code does things but you couldn't in a million years guess why or how you came about it without having a huge history lesson on the company and its codebase.

Now imagine how amazing it is to join a team where efforts are constantly made to name meaningfully and that there aren't 8 concerns mixed into a single god class. New devs join and they immediately understand what's happening in the business because the code translates directly to the reality. They don't have to learn two languages (business and dev speak).

Now imagine that dev having to add a grandfather clause to an old account. Where should he put it in the `Account`, `Plan`, `User`, `Subscription` or `Business` class? When the distinction between concepts are clear in the code it's easy to determine where the code should go and where logic of different kinds should reside.