Full disclosure, I work in the game industry.
Voting with your wallet is something that game companies definitely pay attention to, in the sense that they generally won't do things that they don't think will make money. The problem is that the people who organize boycotts on social media and forums aren't necessarily representative of the people who fund game companies.
Almost everybody who works at most game development studios are gamers who care a lot about game experience, quality, and often have the same experiences with free to play, microtransactions, DLC, that everybody else does. At the same time, though, in order for the studio to stay open, it has to find a way to bring money in so that people can get paid. This is a problem with, like, capitalism, but not with games specifically. Every company, from EA to the Red Cross, has a few people whose jobs are to find a way to fund the work everybody else actually wants to do, so that it can get done.
If someone doesn't like something they can easily load up a social media website and contact the publisher, developer, or the creator. The days of gaming magazines being the only public voice have gone to the wayside. Developers can know how people feel just by following their feed. Some people probably don't mind it, while others are probably just annoyed by it.
So this is true, but there's a big problem with adverse selection here.
If your game is unsuccessful the people who contact you on social media are mostly the people who like it -- meaning that they're not really representative of the people who are causing your game to be unsuccessful. Those people have generally checked out entirely and are not posting on your Facebook page.
If your game is successful the people who contact you on social media are mostly the people who are angry about it -- meaning that they're not really representative of the people who are causing your game to be successful. Those people are generally having fun and see no reason to post.
In both cases the people who make the active step of reaching out are people who feel much more motivated than the average user to reach out and contact the developer -- which means that they probably have an agenda. That makes them unrepresentative and potentially unreliable.
That said, definitely anything you post on social media or first-party forums is going to get aggregated by a community manager and, depending on its frequency, raised as a potential topic of conversation with the dev team. But it's only one slice of data to add to a huge pile of data explaining not just what people say, but actually what they're doing.