If one needs to try and make an economic justification to go out fishing, then you’re going to have a bad time. For the majority of people, cost of gas/gear/time >> just buying them from the fish market.
Being able to keep something for the BBQ is a nice perk, no argument here, but if that’s how someone measures success, then they’re probably going to come out on the short end of that calculation.
As for the OP question, it would be interesting to see how much crowding would be reduced if the limit was raised to 4. Some people would leave right away. Some would release all sockeye after 3 in hopes of a spring. Some would continue to fish and release everything after 4 simply because they’re having a fun time of it out there, and that would be perfectly legal.
And isn't it plausible that raising the limit could actually motivate a lot more people to make the trip out who wouldn't otherwise go and as a result would be just as crowded or maybe even worse anyways?