Why would you assume that?
The system is vision based.
You might not have heard, but Tesla is devoting considerable resources to improving their vision software for additional reasons beyond wipers.
It's already a lot better than it was a couple years ago. I expect it'll continue to get better over time.
Well I did say I was assuming "for the sake of argument". The assumption was intended to introduce my point about the alternative option of adjustable intermittent wiper functionality.
But thanks for the info about Telsa's vision detection efforts - I hope that something comes out of it.