What you're missing is that if you are evaluating the non-trivial investment, you can't disengage it from what makes it a non-trivial investment if you want to do a an honest (thorough) evaluation.
The investment is relevant only insofar as it renders an assault on a PoW-coin unprofitable, for the defense from an attack is what keeps the coin from being valued less for its having suffered some manner of compromise therefor.
I'm trying to determine what makes a non-trivial investment, non-trivial. You are arguing why a non-trivial investment holds value for a crypto currency. What it does versus what makes it do. I'm going to write some poems . I could have written a sestina with the time I've wasted on you.