Merton Share - investment allocation

I recently finished an interesting book, The Missing Billionaires. The major point of the book is most of the old-money names (ie Vanderbilts) etc lost their fortunes through asset misallocation / lack of diversification and that this would be avoidable with placing the right size "bets" in investments. Its somewhat antithetical to search (single large bet) but could be useful in thinking about how to maintain some "safe" capital outside of the one big bet. Throwing this out there as an interesting read.