Minesweeper thermodynamics

The author’s math considers how mines would be distributed if mines were distributed to the empty squares after reaching that board state.

This is wrong.

This is classic Monty Hall Problem. The author is doing the equivalent of saying “there are two doors left, so the odds are 50 / 50 that the prize is behind either door.

It invalidates all of the numbers after this point.

The difference is that Monty knows which of the doors the car is behind and deliberately avoids it, thereby giving away information about where the car is.

Whereas in Minesweeper we've just blindly stumbled across a situation where we have to guess.

It would be like if every show Monty always revealed a random door. Sometimes he would reveal the car and the game would end immediately. In the cases when he didn't reveal the car it really would be 50/50 between the remaining two doors.