Have you read the biography. I haven't. But I have followed the man since first seeing him on PBS's Wall Street Week with Louis Rukeyser back in the 80's.His business model is copyable by anyone with a brokerage account. Sell options/buy stocks/reinvest dividends/repeat endlessly. That is why his biography is called snowball, it refers to the compounding of money in the way described.
I found this, which I believe is from the book, that emphasizes his key strategy:-
In 1962, Warren saw an opportunity to invest in a New England textile company called Berkshire Hathaway and bought some of its stock. Warren began to aggressively buy shares after a dispute with its management convinced him that the company needed a change in leadership. Ironically, the purchase of Berkshire Hathaway is one of Warren’s major regrets. (For more, see: Risks and Rewards of Berkshire Hathaway.)
Understanding the beauty of owning insurance companies – clients pay premiums today to possibly receive payments decades later – Warren used Berkshire Hathaway as a holding company to buy National Indemnity Company (the first of many insurance companies he would buy) and used its substantial cash flow to finance further acquisitions.
So yes it is copyable by anyone who first start with and then continues to control ginormous free cash producing businesses like insurance or trust companies.