Not to defend Tesla, and I don't know the details. But very likely that old replaced battery would remain with Tesla and they would scrap it for parts or otherw

Not to defend Tesla, and I don't know the details. But very likely that old replaced battery would remain with Tesla and they would scrap it for parts or otherwise recycle it into a "refurbished" part to be sold again. Might be they would ask more than $16000 for the repair if you decide to keep the old battery yourself. Other companies apply this as well, it's an economics of scale thing. It's not worthwhile (ie: profitable) for them to have every technician in every service location educated to a high enough level to do low level troubleshooting on every model and every part, it's much cheaper to hire people that can swap out modules and ship those back to a central facility. There you have people that do nothing all day then troubleshoot all parts they have been specifically trained for, repair them and sell them as refurbished. A lot would probably still end up on the landfill. And whether the customer sees any discount in repairs due to this "optimisation" is debatable. But right now you hardly have a choice, I hope that will be changing.