I don't think it's foolish. If very few people are getting directed to your site via search, people aren't posting, and you're getting swarm after swarm of bot registrations and spam, then what's the point in maintaining a forum that takes both time and money that could be spent elsewhere? You're not going to pay to keep 1TB+ of file attachments and whatever else around forever. Bothering with the whole process of moving them into Amazon's services to make it more cost effective isn't worth it to some people running these places either. You can archive/prune discussions too, but you're still storing the data.
I personally like forums because everyone has a common interest whether it's Apple Inc., tech in general, books, specific music, whatever. It makes talking about other things easier in most cases too, and even though you can a lot of times end up talking about the same thing across all these various outlets, they all have very different point of views that are not just from the tech savvy/bookworms/audiophiles/etc. Like here on MacRumors, there's obviously a lot of people who don't care for Android, but it's good to be able to talk to people who use a Mac like you and are interested in using a Samsung, HTC, etc, and have also come from an iPhone.
With social media, you can have your one account that people talk to, you retweet, you make hashtags to make it easier to follow in search/clients, and discussions happen in a frame of a hour or whatever. Plus when people want support for something, it comes from the person/team who can answer 100% correctly (not as problematic around here and probably the tech space in general, but I've been on places where about 20 people all answer incorrectly because they clearly didn't understand what they had read).
I don't like it as much either, but I know why it's a "better" alternative.