Given how absolutely critical sensor data is becoming to aircraft software, it seems like airplanes should probably have a dozen redundant AoA sensors and pitot

Given how absolutely critical sensor data is becoming to aircraft software, it seems like airplanes should probably have a dozen redundant AoA sensors and pitot tubes. And the sensors should be of different design and manufacture, so they're unlikely to all fail under the same conditions. It seems like the Air France 447 and 737 MAX crashes could have been avoided just by having highly redundant sensors. This is probably what will have to happen for fully self-flying aircraft, so why not do it now with partially self-flying aircraft?