"In the past, our forums were the only way we could speak to you directly. They allowed our developers to talk with fans, and gave our players the opportunity to talk with each other about our games. But with the rise of social media and geek culture, there have never been more ways for us to connect. http://blog.bioware.com/2016/07/29/concerning-our-forums/
I have yet to see social media equal the interaction quality of Forums. Also when a company does this, they hand over control of their message to third-party companies who have their own terms of service which they have no control over. Forum management costs a lot of money (mostly because forum software tends to be only mediocre at handling spam and low-value content).
I've seen other companies go down this path and the engagement drops like a stone. People simply stop trying to stay connected and up-to-date on current events. They either use your product or they don't and they find themselves in an information vacuum. As far as I am concerned, this is a cost-cutting measure pure and simple. And it's easier for companies to justify just shutting them down rather than migrating from vBulletin, IPB3, or phpBB to XenForo. Forums are being declared an unaffordable luxury.
I think a large share of this blame can be rested firmly on InternetBrands' shoulders. After years of having the market leader -- which kept competitors off the market and from even TRYING -- then they ran vBulletin into the absolute ground. As a result, there was nobody to step up and take over.