There are a few clear themes to point to here that can illuminate exactly where the rot stems from. The overarching theme being monetization — or, more specifically, increasing external pressure to monetize these social services.
Also worth emphasizing: human time and attention span are finite, so any digital service that steers you away from the things you are actively interested in for its own profit-making ends is acting parasitically.
Source: There’s Something Rotten In The State Of Social Media | TechCrunch