Here is a thought. When and if a battery needs replacement due to a warrantied issue, is Tesla obligated to replace with a new battery pack? Can't they replace with a refurbished pack? This could be an outlet for their swapped packs with some discount passed to new P90DL owners who want to trade up. This could also save shipping costs to and from high volume SCs. Btw, your analogy wasn't that bad, except I would not try to noodle around with my battery with a fork unless it was a plastic fork...
They used to replace with refurbished packs, but people complained that they were potentially getting older/abused packs when they had babied theirs. Since then it seems they only repair packs: they give you a loaner pack while your pack is sent off to be repaired. So your original pack comes back to you.
Since they don't currently offer other upgrades what are they going to do with these returned/used 90kWh packs? They could use them for loaner packs, but I don't know that they need many more of them... So they will likely get torn apart to use for parts to repair warranty issues on other packs. I think it would be best if they would offer upgrades using "refurb" packs, but I don't know that they would have enough packs available for the potential demand... (It is a chicken/egg problem.)