"Maybe the idea is that if you have a money threshold, you will limit the number of people who casually fish and therefore you decrease the overall impact."
The idea is that the government likes the money, and if they consult at all, they ask organizations of joiners, who happily trade off the rights of the casual fisherman who doesn't joint their organization.
I've been a catch and release fisherman for 40 years, and a fly fisherman for 35. Used to tie flies and make rods for money around the time I was in university, make bamboo rods these days, though not for the last several years.
The whole idea of catch and release is to produce sufficient stock to allow a larger industry to flourish. One person's, too valuable fish, is another person's meal. There is more money in the industrialized fly fishing so that gets the nod from a lot of people. It's a blood sport like cock fighting that has seen a lot of damage in the form of intentional spreading of non-native genes, dilution of resident genes, spread of disease, and individual messing around with sentient living creatures. But that's what it is, and I still love it.
There are very few fisheries than can create interesting fishing experiences from natural production. Educated trout, along with a kill. High yield fisheries tend to be boring, though it is something to get the blood going in the early season.
Catch and release is just a step on the way to the next form which will likely be some form of privitization, or limited access. All it does is increase the number of fishermen a resource can support, over time the impact is too great on the fish, and one is back to a loosing proposition. Not everywhere, for every species, but it isn't a complete fix.