So Warren Buffett became a Millionaire at the age of 32 but it took him 24 years to go from 1 million to 1 Billion.
Compare that to Tech billionaires and especially the top 10-20 richest people, like Bill Gates, Zuck, google founders, Musk, Bezos etc. this seems very slow indeed.
But it makes sense given his methodology of Value Investing. All the other richest people in the world are founders.
I think Buffett is a only one of handful of people who got to be one of the richest people in the world without founding a new business or starting a company (Birkshire is an investment holding company so it does not really a count as new business or industry in and of itself).
Value Investing is slow.