When the average person stops spending money in ways that enrich them.

Individualizing systemic failures to regulate businesses is counterproductive. Meaningful change will only come by regulation.

Give me one example, where consumer behavior really changed anything. Usually what follows from large boycotts is political action or the company succumbing to pressure.

Just stopping to spend your money there might make you feel good but don't kid yourself, it barely does anything if you're not turning it into an organized action.