It’s good you have articulated these points. However, I assume any serious designer will already know that so-called “design principles” documents are 90% vapid drek, so will typically ignore them anyway. And those stakeholders who aren’t designers will do the same for similar reasons.
The mystery is why designers don’t do something about this. Why don’t we see more real design principles written down and used? The examples are incredibly few. Fear? Laziness? Lack of time? Or is that most people who call themselves designers aren’t in fact capable of formulating principles that make sense?