I doubt he has evidence for that, although sample sizes are small enough in most wars where you care about odds at all that unexpected outcomes can really screw you, and the investment to make it nigh-impossible is cost-prohibitive. That's bad game design, because ideally you'd want players to trade between "I can win this guaranteed", "I will usually win this", "I might win this", "I probably won't win this", and "I can't win this" based on plausible degrees of investment.
In civ IV, in the early game it is absolutely impossible to get "guaranteed" while in the mid-late game the difference between guaranteed-win investment and "might win" investment is trivial; that's why everyone will say things like "I know this game is won."...and be correct despite victory being 50-100 or more turns away.
But why the divergence? It doesn't make sense that the outcome of very long games can be decided at nigh-random in the opening turn sets, only to stabilize to the point of every non-broken-event factor being *extremely* minimal on a per-rng basis. Probably the biggest offender is spawn location (god is this awful in civ IV, and barely any better in V), but barbs, "early rush" situations, and huts/events if one leaves them on all follow the same pattern...RNG is potentially GAME BREAKING early and completely irrelevant later...with only the most asinine and ludicrous events (bermuda triangle, forced DoW) being exceptions.
Compare the axe rush to the cannon attack at tech parity. The former is absolute RNG hell, and yet could easily be an optimal choice since it's the only way you can win a given map (very boxed in). The latter is FUNCTIONALLY deterministic combat, in large part due to collateral. This is part of the reason I always found the people who STRONGLY argued against deterministic combat to be using questionable logic. With the way wars after the early game go, collateral initiative, positioning, and very late game nukes ARE the wars...RNG is non-factor.
Show me the last time the RNG screwed someone in a Rifle-cannon war
. That's deterministic combat, or more accurately mathematically so close that the difference is negligible. Why, then, can't we have it at the beginning of the game also? This *is* a strategy game after all...and the vast majority of it actually works off of strategy, go figure! But not early on. Nope. Somehow, people hold that sacred too lol.