The core issue is the underlying system that values engagement over all things ... the advertising system.
I don't think you're digging deep enough here. It's not the business model. It's the technology.
We've invented technology that can, to a significant degree, control people. It is as addictive as hard drugs and people will just keep coming back to their dealer for more and more digital crack.
But it's worse than simply heroin or crack cocaine. It gives the dealers not just the power to keep people coming back for more, but also gives them far, far more control over not just what those people do, but what those people think.
The large companies (Google, Facebook, Twitter, etc) aren't in the business of search or social media. Nor are they in the business of advertisement. Their business model is selling complete control over people at the population level. At some point it will stop being a business model and start being a self sustaining model of raw power that strips us of our humanity.
We need to take a hard stance to all attempts at psychological manipulation via technology. A/B testing to see how changes affect behaviour should be seen as morally repugnant as selling crack cocaine to children.