Engineers need to understand that those requirements don’t apply to every project.

https://res.cloudinary.com/monday-blogs/w_1000,h_561,c_fit/f...

How does an engineer know that he is involved in a bozo-driven PoC or in a technical deathtrap that will end up as the core business of the company?

Again, by communicating. If someone doesn't know what they are building, who they are building it for, and why -- then they do not have a solid grasp of the requirements.

Never saw a subcontracting requirement document, stating "the solution is for a bozo-project. so don't spend ages making it robust for the future"

Effectively communicating as an engineer is not “reading a requirements document”.

If you’re just blindly implementing someone else tech spec, you’re not doing any engineering, you’re just programming.

Oh, that's easy. Can you point any real person waiting to use the thing?

In fact, that's probably the easiest question to answer on this entire discussion.