Car with a good maintenance should last 20 years. Not like a phone that gets thrown away every 5 years.
Unless its changed even more recently - they _do_ publish a parts catalog.
And every single item, down to the most commodity screw/bolt doesn't list a price, just says "Contact Tesla for Sales". And according to at least a few people who have indeed contacted them, "Sorry, that part is not purchasable".
Basically as if a state said they had to make parts available to be (potentially) purchased online, and they had followed the very letter of the law.