The Vegas books had already pulled the fight off the board. Casino in Reno held a single posted price at 42-to-1, took less action than the rest of the city combined, and watched the math run the other way. The lesson wasn't 'Tyson can lose.' It was that a price that looks free is the one nobody is selling, and there is always a reason.
If the line moves to a number nobody else is offering, that's almost never the value bet. It's the bet the market has already decided is mispriced and refused to take. The Reno book got famous for one ticket. They are far better remembered for the hundred others they made by quietly declining the prevailing price.