You can’t adapt when the zone is completely different one pitch to the next.
They have all the technology for anyone in the world following the game on tv, or an app or a computer to know if a pitch is a ball or strike, except the guy who makes the call. Not to use it, while it also in no way slows down the game like replay is just dumb.
Since umpires don’t care to get better at this aspect of the job anyway, screw em. Don’t need em to continue to do it.
Most umpires are pretty consistent. The top 10 umpires for balls/strikes are north of 95% in both accuracy by pitch f/x and in consistency. I'm sure robo umps can do better but most umps are pretty good most of the time.
I also strongly suspect that if you were to incorporate robots to enforce the official definition of the strike zone you'd get some weird looking calls and we would end up having to moderate some of the extreme cases. For example a ball that grazes the top of the zone near the back of home plate, or grazes the bottom of the zone near the front of home plate, is going to look really off and unhittable in many cases. We could fix this by telling the robots to only call a strike if the ball's trajectory through the strike zone covers at least a certain distance from front to back.
Keep in mind that pitch fx isn't 100% representative of the zone because the zone is 3 dimensional.