It was my understanding that such redundancy for automation purposes did not even exist, and that despite having 2 AoA sensors only one was selected before a flight, with the computer switching the one to be used between each flight.

Also Southwest certainly did not have all of the indicators at first, because they added some: https://theaircurrent.com/aviation-safety/southwest-airlines... (note that pretty much nobody used that kind of indicator before, so I don't say that to put blame on Southwest)

It was also my understanding that some alarms including the AoA disagree were optional and for a fee even though probably activated by only needing to switch a bit somewhere in the software. So if Southwest had AoA disagree from the beginning (I don't know), well that's cool, but my interpretation is more like: that's not cool that some other airlines did not have it because of the dubious commercial practices of Boeing.