Interestingly, this is one of the theories for why Tesla's parts situation sucks.

While you could also argue that they make things complex for themselves by having these rolling updates rather than using a Model Year system...

Elon, as is well known, is FANATICAL about the quarterly numbers. Burn the midnight oil to pump up the deliveries, etc., etc.

The thing with that, every part that's on a shelf waiting to be sold for warranty or accident repair is a part that can't go on a new car and boost the numbers. Wall Street doesn't give a shit what your parts market numbers look like, it's "How many Teslas did you build this quarter?" so there's a lot less incentive to fully stock that market - Tesla already has the sale booked and the money in their balance book.