[erictd]

Since there are zillions of Model Ys out there, what will the replacement battery market look like when mine finally fails in n more years? Will there be relatively inexpensive batteries with the same kWh as mine? Will there be more expensive batteries with more or much more storage available? I guess I'll find out.

[theshrike79]

There's already a secondhand market that replaces and upgrades Nissan Leaf batteries.

Same goes for Teslas. The official Tesla service will always replace the whole slab for massive $$$$. Smaller independent shops (mostly self-taught currently) can replace individual failed blocks from donor batteries pretty cheaply. (Less money than an head gasket change or a clutch replacement.)