I'm not an expert on this but my understanding is that primary goal of these culling efforts is to study the effects. The urchins have created barrens and the kelp has been greatly reduced. The urchin problem is not totally understood, but some contributing factors are that the primary predator of urchins in Norcal is the sea star and the sea star population has been decimated by sea star wasting disease. The otter population was nearly wiped out in the 1800s. Also, rising temperatures can be part of the problem.
So, to answer your question, no, it's not a definitive answer to the urchin problem. For me, doing something and studying the effects is better than doing nothing. Urchins are a necessary part of the ecosystem, but even they are suffering from overpopulation. They're reducing their own food supply to the point that their growth is stunted.