chiming in briefly. I am an investment professional. With the market performance we have experienced over the past 10 years (S&P up 16% on average per year), we are very likely to be entering a much lower average return stream in the near future. The last 10 years were a huge anomaly, as US equity markets have averaged approximately 9% per year since the Great Depression. If you remove the last 10 extraordinary years, it is 8%'ish. Our expectations for just the US equity portion of a portfolio is 5-6% per year on average over the next 5-10 years. If you then diversify some of these holdings into bonds, the portfolio return drops further on average.
You also need to factor in inflation, taxes, fees, etc to get your net return rate on the portfolio. Remember, any income is taxed from a portfolio (dividends, coupons), and any gains realized are also taxed. I'm not saying anyone's assumptions made here are wrong, as anything can happen, but there are many factors that go into a 'set for life' analysis. In DM's case, age would certainly also play into it. To be conservative, expect someone to live to 100. In DM's case that is 76 more years. I would argue that $2M would hardly be sufficient for any family over a 76 year timeframe - especially once kids, etc are factored in.