I've bought many new cars, ranging in price from a $20k VW to a $95k Volvo, and my almost new $120k Model S. All of the new vehicles were immaculately clean and well presented. Yes, dealers have cars sitting on lots or storage yards for weeks or months, but they clean and detail them prior to delivery, and the manufacturers obsessively survey their customers after delivery to see if they were satisfied. This is doubly true of $80k cars, to the extent that a franchise dealer for a premium brand would probably lose its franchise if it repeatedly delivered dirty and scratched cars and risked customer rejection / complaints to the manufacturer. This is the normal, well-established way that new car sales work, and it's what buyers rightly expect.
I'm just bewildered by the statement that no car buyer ever cared before, as if Model 3 recipients should be so grateful that they are getting a car at all. The OP isn't complaining that his car was left somewhere exposed to the elements before he picked it up; he's saying it wasn't properly cleaned and prepared for delivery. The solution isn't for customers to adjust their expectations downwards but rather for Tesla to find a way to scale its delivery process properly, for the good of Tesla as much as for the customer. The last thing they want to do is send cars out that aren't properly prepped and then incur the greater cost of remedying this after the fact.