Best guess is that they were all caught up in the arms race to try and make a better model, at whatever the cost. And if you work in this space you were probably getting thrown fistfuls of money to join in on it. I read somewhere on reddit that anyone trying to push for efficiency at these places was getting ignored or pushed aside. DeepSeek had an incentive to focus on efficiency because of the chip embargo. So I don't think this is necessarily a knock on US AI capabilities. It is just that the incentives were different and when stock prices are going to the moon regardless of how much capex was getting spent, it was easy for everyone to just go along with it.

With that said, I think all of these companies are capable of learning from this and implementing these efficiency improvement. And I think the arms race is still on. The goal is to achieve super human level of intelligence, and they have a ways to go to get there. It is possible that these new efficiency improvements might even help them take the next step as they can now do a lot more with a lot less.