It's pointless to have million-mile batteries except for commercial vehicles like semis. For consumer cars, the rest of the car will only last 250k to 350k miles. I've seen some cars with 250k miles (not Teslas). The dashboard plastic is decomposing, the paint is peeling, the seats are torn, the steering wheel wrap is hanging by a thread, the chassis is rusted out, etc. That's before getting to the mechanical problems.
And with the way Teslas are built and designed, it's even more pointless to have a battery lifespan of >200k miles. The paint can't even get to 50k miles without dozens of paint chips