I think that reasonable assumptions that they can't change over their entire production of batteries and product offerings all at once, lead people to think that the Model S and Model X will receive the updates first.
Not even "the S and X"
Just the S. And only the new Plaid P $140,000 version.
(price is somewhat speculative, the fact it'll cost a lot more is not)
Then the Plaid X some time later.
Because they simply won't have the production capacity to introduce anything else by September this year.
Regular S/X will still get the 18650 cells they signed an added 2 years with Panasonic to produce.
The ramp up of new cells beyond that will feed cybertruck and semi initially.
It'd be absolutely insane for them to rev the 3/Y battery just a few months after the Y launch. (plus as you note- they lack capacity to produce them in volume so anything other than explicitly mentioning they're NOT doing this for YEARS yet would tank current 3/Y sales which they can't afford to do).
Whenever these improvements do arrive, the vehicles without the improved battery will almost certainly depreciate. How much really depends on how big of an improvement Tesla is able to deliver.
Did the P/S85s depreciate a bunch when the 90s came out? How bout when the 100s came out?
I don't honestly know the #s, but I don't believe it was especially significant.
Last I knew the biggest depreciation difference was if it has AP1 vs AP2 since AP1 was dead going forward....the battery difference didn't figure in a ton.
The S100 already has over 400 miles.... do you really think it's gonna hurt resale of that car if suddenly there's a new 500 mile one?
How many folks routinely drive over 400 miles a day?
For me, I decided that I don't really stand to gain anything buying the M3 now instead of waiting 2.5 months. I am working from home right now and not driving much. There is no issue with me continuing to drive the vehicles I currently have for a bit longer and I might get a better car in the long run by waiting. Other people, I am sure, are in different positions. Also, I may wait until September and then find out that the new battery is not coming for the M3 until Q3 2021 or something.
I mean- if it doesn't matter to you to wait (other than you're gonna pay a bit more for FSD if you planned to buy it) go ahead and wait... but I think you'll be disappointed at having done so.