So there’s the problem. This should be sufficient?

exactly

and top is complaining that his industry was instead given unholy ammounts of money to agrue that it isn't.

Browsers removed the Do Not Track header because it was... used to track users.

This should give you the answer to "why this isn't sufficient". The ads industry does not respect anything until it's driven out of existence by fines.

So would a law that makes illegal to respect it + actual enforcement of said law be the missing approach here?