The point isn't that avoiding scarcity thinking magically provides a solution. It's that it's very difficult to implement a solution when you have e.g. a lot of fishers who stand to lose out from it.

The idea is that we should work towards a society where the people who currently fish are happy to stop fishing if necessary, because they don't fear for their survival or comfort if they do.

I'd agree it's not really a good short term solution to acute problems though.

Fish farming. Growing fish meat from stem cells. Finding substitutes for fish meat, e.g. via synthetic biology from fungi.