This means that variance is not just "psychological", there is a real economic cost to variance. These days you might get away with saying that if you're a Vulcan you're better off mining solo, but in the future when mining will be one in a million chance to get $100M even that much won't be true.
That's incorrect. Even at insane difficulties solo mining pays more on the bottom line. The chance to find a block solo decreases as much as the average payout of a pool, the relationship between both stays invariant.