The utility of money is concave, logarithmic is a good model. It's expected utility you need to maximize, not expected money.

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.

And we're not Vulcans. Trying to mine solo caused me to lose sleep. Plus, some pools have convenience and monitoring features, and in the future end users won't be able to run a full network node.

Only if you think mathematics is about extremely oversimplified models completely detached from reality.