Last but not least, any non-index based plan is destined to fail anyway, because sooner or later someone will come along and convince your spouse to tinker with the portfolio.

Or worse. In the 1970s, I had a distant relative that had money (he was the only relative that had money). He died sometime in the late 1970s and his wife inherited his money. A few months later someone convinced her to switch from the broker that her husband used for decades to a new younger "more dynamic" broker (I dimly recall that he was recommended by a nephew of hers). Anyway, within the first year, that new broker sold ALL her individual stocks, that were all very long-term holdings with a tiny basis, and put the money into an assortment of "safe" mutual funds. And every single mutual fund that he put the money into had a load, mostly 4.75%, but some a little higher. The story he told her was "diversification". And of course, the next time we saw her about a year later, she bitterly complained about her massive tax bill that year (all long-term capital gains). Even as a young adult at the time, I instinctively knew that it was a mistake to do so, to realize so much capital gain for someone in their late 80s. Sure enough she died that year (1979 or 1980). It didn't matter to us because we were nowhere in the list of heirs, but the estate went through probate (he had various trusts set up to mostly avoid probate, but apparently she did not). My dad and I calculated that because of the rash actions of that broker, probably $1.5M to $1.7M was unnecessarily lost to taxes, and another $250k to $300k was lost on unnecessary loads for those mutual funds. And to add insult to injury, there were also estate taxes to be filed and paid above and beyond the previous planning mistakes.