With battery packs probably you can do some smart things to make the degradation curve look more linear, but again there is only so much you can do.
Also in RC car world it's generally preferred to have one cell per voltage step, I've had way more dual-cell(per series) packs fail than single ones. Though my experience is only 6s/~22v but it's "the same shit on a bigger scale" as far as I can comprehend.
I have often wondered if it would be worth designing an EV battery that can permanently short out a bad cell in a string, perhaps by deliberately disabling balancing, letting the bad cells voltage fall to zero, and then perhaps having a single use 'bypass' that latches on.
It wouldn't be a seamless user experience, because if you discharge the cell to say 0.5 volts but then the user tries to charge their car, you can't let them, since you cannot safely charge a lithium cell which has fallen below the minimum voltage, but you also cannot bypass it till the voltage falls to zero. Could be done automatically at 3am though like system updates.
Either way you need some form of overbooking / compensating capacity.
My car's high voltage circuitry seems to work down to about half of the nominal voltage.
Search this page for "PTC": https://www.electricbike.com/inside-18650-cell/
The PTC protects the rest of the battery if a single cell internally fails short.
You could have a two-way bypass, disconnecting the original cell, but that would cost more. Remember the bypass switch is duplicated for every series cell group (hundreds) and must carry the whole battery current.
Or you could have some kind of slow drain resistor - but then you're back to the time issue.
You don't, if one cell fail you shut off the whole array of cells that is in series. But a pack has several arrays of cells.
If it happens multiple times in the same module you replace a whole module of cells. The packs can usually be disassembled and parts replaced, but the modules are usually soldered down to prevent/mitigate thermal runaway.
Also you can't mix cells of different chemistry or capacity together in the same module. So really if one fails in a module you replace the whole module. Or, in their case, just keep the module there disconnected until the whole battery fails then you scrap the whole battery pack. I assume it is not worth it for them to do any kind of replacements.