This is not accurate. Protests vary in degree, location, context, and methods. Protests like Stonewall, Mayday, Women's Suffrage, Arab Spring in some places, and MOL all had different influences that directed history in some way and changed quite a lot.

It would be more accurate to say that generally speaking protests don't amount to much beyond bringing awareness to the public.

It's also not accurate for OP to claim that the current protests haven't amounted to much since some are ongoing. The Iranian protests have spread throughout their country from schools to businesses and regime change is a potential outcome if the pressure remains.