Residents of California have the right to opt out, no?

In theory, they also don't get spam calls.

Opt out from snake oil salesmen.

Yea sure. If it helps you sleep better. It is the law.

In reality the data is already 'grey market' so I doubt the law matters to them.

Disappear and new data broker sets up shop. You think these people are regulated? I bet they swap datasets like Pokemon.