The automatic wipers on non Tesla cars use infrared sensors that have existed for decades, so they're a well known quantity. The Tesla wipers use the front came

The automatic wipers on non Tesla cars use infrared sensors that have existed for decades, so they're a well known quantity. The Tesla wipers use the front cameras to detect rain, and those cameras are focused at a distance that's far enough to be able to see other vehicles, so they're not focused on the windshield, which is why they're unreliable.