The key question here is if Tesla is going to ever retrofit their new cells into the old pack format.
There are really good reasons to and not to.
If they did, they'd have to match the weight and volume of the existing pack (there are 2 or 3 weights and I think they all have mostly the same footprint).
I'm hoping that tesla will support a 2015 S reasonably well in 2025, which would include "replace the pack" for $10-15k.
Maybe yes maybe no? Remind me in 5 years to update this thread...