[marcosdumay]

Mechanical CADs aren't designed for maintainability.

They are designed for expressivity first, and easiness of learning (for people with industry knowledge) second. And those are the two only goals.

Just try to adapt a mechanical design for a slightly different task. It's usually better to start from scratch.

(Anyway, that's an example of computers not being fully used. Going from the Solow paradox into "computers are bad" - like lots of people like to do, even here - is just stupid.)