Berkshire is a money making machine with or without Buffett. Its market cap is 30% lower than Tesla, while it brings ~100B / year in net income - most of which is from very stable, boring businesses.

As Warren liked to say: "I try to invest in businesses that are so wonderful that an idiot can run them. Because sooner or later, one will".

That's his portfolio now - he won't promise robots or AI, but he can guarantee solid profits for 10 years to come, regardless of his presence.