If you want to get an idea of how quickly sentiment has shifted against U.S. tech giants, just listen to NYU professor Scott Galloway.

The marketing professor is a self-professed fan of companies like Facebook, Apple, Google, and Amazon. He’s made a bundle owning their stocks, some of them are clients of his, and he even wrote a book last year called The Four: The Hidden DNA of Amazon, Apple, Facebook, and Google.

Over the past two years, Galloway’s annual talks at the DLD Conference in Munich analyzing their prowess and success have gone viral on YouTube. (See his 2015 and 2016 talks embedded below.) This week, however, Galloway returned to DLD to give a talk called “The breakup of big tech” that cast the four in a very different light.

“This started out as a love affair. I want to be clear,” he said. “I love these companies.” He then shifted gears: “After spending the majority of the last two years of my life really trying to understand them and the relationship of the ecosystem, I’ve become 100 percent convinced that it’s time to break these companies up.”

It’s an audacious claim from anyone, even more startling coming from someone who has been such a close and bullish observer of these tech giants. Yet for Galloway, it is clear that the four companies have simply become too big, and too powerful.

“The premise of my book is that Amazon, Apple, Facebook, and Google are our new gods, our new source of love, our consumptive gods,” he said. “And as a result of their ability to tap into these very basic instincts, they’ve aggregated more market cap than the majority of nation’s GDP … I think these entities are more powerful than any entity, with maybe the exception of China and the U.S.”

Galloway said he wasn’t making his argument based on