Communication happens in the mediums available to people. You didn't have Facebook in those days, so people posted flyers. Now most people are on Facebook, so events are advertised there instead. You might see a posters for event sometimes, but I hear about local events through FB all the time. Particularly since friends of mine mark that they will attend or are interested, and they then appear in my feed.

I agree with the argument that FB is just using us as their product, and that's not great. However, disregarding that, it's simply a useful tool to communicate with people! To avoid the shittiness, just unfollow the people who post tons of bullshit, and get some interesting friends.