There is no incentive to fix that because it isn't broken for the likes of Facebook. Of course for the rest of us there is a huge incentive. But it raises the question of how. How is it going to work, and how are you going to convince people to use it. The first part has lots of answers in the form of social networks without a lot of users. So, the latter part is the problem.

As for authenticity and integrity; some notion of using cryptographic signatures could work. It's not particularly hard. News especially should only be coming from authentic sources. It's such a low tech solution to just sign your work and stake your ruputation. But somehow that's not a thing. Instead, our social media feeds are full of crap from dubious sources. Because click bait works and sells clicks.

That points to a solution. The likes of Facebook should start authenticating sources of information and start accounting for reputability. They are obviously incentivized to instead serve you clickbait. So the solution is to incentivize them otherwise. Hold them accountable. They help spread misinformation and profit from it. That could have consequences. When it does, Facebook will adapt.