The real question here is whether websites are entitled to that traffic, or even more specifically, to human eyes - and to what extent that should allow them to override users' preferences (which are made fairly clear by the very act of using Perplexity in the first place; the reason why you'd do it instead of doing a Google Search and then manually sifting through the links yourself is because most of what you see is garbage).

I would even argue that the whole conversation about AI is a distraction here. Imagine if, instead of using an LLM, Perplexity actually assigned a human agent to your query who'd do the same thing that the model does: write the search queries based on your high-level question, read through the pages that come up, and condense it all into a summary with references to the original sources. That would, of course, be a lot more expensive, but the output would be the same, and so would be the consequences: the person who asked the original high-level question does not get exposed to all the content that had to be waded through to answer it. Is that unethical? If not, then why does replacing the human agent with an AI in this scenario becomes unethical?

And if the answer is "scale", that gets uncomfortably close to saying that it's okay for the rich but not for the plebs.