Julian Schrittwieser (author of this post) has been in AI for a long time, he was in the core team who worked on AlphaGo, AlphaZero and MuZero at DeepMind, you can see him in the AlphaGo movie. While it doesn't make his opinion automatically true, I think it makes it worth considering, especially since he's a technical person, not a CEO trying to raise money
"extrapolating an exponential" seems dubious, but I think the point is more that there is no clear sign of slowing down in models capabilities from the benchmarks, so we can still expect improvements
Benchmarks are notoriously easy to fake. Also he doesn’t need to be a CEO trying to raise money in order to have an incentive here to push this agenda / narrative. He has a huge stock grant from Anthropic that will go to $0 when the bubble pops
