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.
If it's about political controversy then there's also a chance that people will buy the game because of it. IIRC the Modern Warfare makers saw that controversy was a huge PR boost for them.
Second, I don't think the enthusiast communities are nearly as big or influential as they think they are in proportion to the whole consumer base. The next glitchy mess of a rehash game EA shits out and demands $70 + your medical history for (DLC not included) is gonna be an all time best seller in spite of poor customer reviews. PR trumps wallet-voters every time.