If you want a short summary, it's this: everyone who spoke is angry about some aspect of these companies but (and this is kind of important) there is no consensus about why and the reasons for their anger is often contradictory.

What could have been a useful and productive discussion with these four important CEOs was anything but. What could have been an actual exploration of questions around market power and consumer welfare... was not. It was all just a big performance. And that's disappointing on multiple levels. It was a waste of time, and will be used to reinforce various narratives. But, from this end, the only narrative it reinforced was that Congress is woefully ignorant about technology and how these companies operate. And they showed few signs of actually being curious in understanding the truth.