Yes, he could do that, but nobody does it every time he disagree with the call. Sometimes, he might trust the catcher more than himself. And, yes, the pitch calls are a team work between the pitcher, the catcher and the coaches. But, I still think the catcher is the most important part of it.
BTW, I haven't watched any of the Cardinals game this year. How come their record is so good? I think nobody expected this, right? Are they going to start losing more, starting today?😁