The window is doing a lot of the work. These are the months where every series
involved exists, which is May 1953 onward. Pick a different start and the answer
can change sides. That is a fact about backtests, not about these two mixes.
Nobody earned these numbers. They are index returns. A real holder paid a fund fee,
paid a spread on every trade, paid tax on dividends in a taxable account, and rebalanced
late or not at all.
The worst fall is the part that decides it. A number you can read in a second took
years to sit through, and the mix someone can hold through a fall beats the one
they sell.
Run your own mix on the
backtest, or put your real accounts into
the
drift calculator and see where the next contribution should go.