I'm not talking about boycotts in general, like say the Montgomery Bus Boycott, because we know those can work. I'm talking about "Company that sells product made me mad" boycotts.
Whether it's past ones like the infamous Call of Duty: Modern Warfare 2/Left 4 Dead 2 boycotts, or more recently like the brewing chud Pride Month boycotts (And if we're being brutally honest here on the flipside: The all-but-in-name boycott of that Harry Potter game a month or 2 ago), all of them seem to universally fail spectacularly and not impede their targets in any way.
Boycotts work and to make them work you need to effectively organise community and people to realise your power. This is why the Montgomery Bus Boycott worked
Shouting into the twitter/steam forum void does nothing