The one problem with that is that before, the inconsistency likely balanced out. With the robot, the strike zone is effectively widened by 3 inches on each side, top and bottom, giving the pitcher a huge advantage. Maybe require the ball be half in the zone as a compromise.
But it didn’t. That’s just not the case - the inconsistencies do not balance out at all. Umpires are quite different from each other, have strong biases towards certain pitchers, are fooled by framing, and don’t even call pitches the same way based on the count; on two strike counts their strike zones expand. Young umpires are significantly better than old ones. Within a single game it is not at all uncommon for one team to be significantly favored by inconsistency in ball and strike calls.
As to the idea machines will call a wider zone than humans, there just isn’t any data to support that. Human umps are actually more likely to blow a call by turning a ball into a strike than vice-versa.
It should be noted that the use of technology has improved umpire performance already- accuracy is up from 10-15 years ago because data from Pitch/fx and Statcast has been provided to umps to help them improve. It’s still not great, though.