This kind of behaviour stinks and I was hoping for something a bit more positive than nothing can be done
Of course it does, but no-one's to blame for the lack of prosecutions as there's no way a single person can be shown in court to have caused damage. It's just the way it is.
On the other hand loads more and better notices would help. EH have a responsibility not to say nothing more can be done until they've done all they can.