You want great fish runs of the good ol days than build a time machine and go back in time. Because not only do you have to get rid of the dams but the what about the thousands of people that live on the river banks that pollute the system or the gill netters that take a big chunk of fish out. Too many things would have to change to get the runs back. There's probably a hundred more reasons as well. Don't get me wrong I'd love to see the rivers full of fish, but I've never seen it so what we got now is pretty good for me.
Personaly I've been having the time of my life the last few years. Plenty of fish for me just to many surfers sharing them.