And which miner SPECIFICALLY would do that? There are only like 7 major mining pools. Which of those 7 do you think would do an attack?
The miners were the ones who helped create Bitcoin Cash. Why would they attack it?
The miners are the largest supporters of big blocks, so it make no sense that they would attack the thing that they helped launch.
Also, people don't seem to realize that it is already possible to do a ~20 percent selfish mining attack. And yet we don't see THAT happening...
These attacks aren't realistic in practice because it would be immediately obvious that something is happening, and the miners would lose all their money as Bitcoin crashes.