Not to sound like a conspiracy theorist, but my first thought was that the MLB is doing it on purpose.
Umps don’t want the robot. They hate it. They take pride it what they do. This is a legal way for the world to see how bad the human eye is.
We have the tech. Why not get the call right every time? They do it in the minors and I love seeing it. It’s vindicating when batter challenges and he’s wrong.