As somebody from the U.S., I'm struck by how much people from the U.K. value a strong background in theory. At Google my experience has been "what matters is how smart you are, whether you understand the problem we're trying to solve, and whether you have creative solutions". When I applied for DeepMind some time ago, I was grilled, rapid-fire, a hundred questions covering the breadth of a rigorous undergraduate education in linear algebra, stats, ML, calculus, etc.. They seemed content to measure my intelligence by seeing how rapidly and deeply I had assimilated standard courses, rather than by seeing how I approached a problem I'd never seen before.
This guy is obviously talented, but also he comes from a tradition of optimizing for this kind of academic culture. You would be similarly weirded out by the leetcode fetish in tech if that's not what you were used to. I think that's what many commenters are missing.
I've noticed that cultural difference too. I think there are things to take away from both approaches. Extremely knowledgeable people with a lot of background in theory should get better at understanding and creatively applying that knowledge to new problems. And people who are great at problem solving should learn more theory instead of expecting themselves to just materialize the best solution out of thin air.
This guy is obviously talented, but also he comes from a tradition of optimizing for this kind of academic culture. You would be similarly weirded out by the leetcode fetish in tech if that's not what you were used to. I think that's what many commenters are missing.