Yes, but I always found that objection a bit silly. It's like pointing out that real cows are obviously not perfect spheres nor do they live in a vacuum.
> [...] if prices perfectly reflected available information, there is no profit to gathering information, in which case there would be little reason to trade and markets would eventually collapse.[2]
That's a stupid way to formulate this. Markets wouldn't "collapse". They would get slightly less efficient until equilibrium is restored to where arbitragers can make enough money to keep prices at that level of efficiency.
Maybe not "collapse" in a the sense of going to zero but if there was no profit to trading, then the quant trading industry would not exist, trading profits would collapse.
Meanwhile Two Sigma is hiring alpha quants to be AI research scientists at $250k starting salary + bonuses.
Even if we're just talking about the HFT/sell-side, there clearly exist various anomalous inefficiencies that can be exploited.
As I said, if we woke up this morning and prices were magically efficient in an idealised sense, at most a few quants would go home and retire early, and tomorrow we'd be back at the level (in-) efficiency that allows people to be market makers.
