Regulation is theater, effectively, thanks to regulatory capture.

This is a false argument. Regulations are effective. When was the last time you breathed in second hand smoke while eating dinner? Or inhaled lead from a passing car? Or asbestos from your neighbor's new house?

Defeatism will always be defeated

For now, it is, yes; but we must both plan for a future when that might not be the case, and advocate for effective regulations regardless.