Edit: this is in the US. Other comments seem to indicate the opposite in the UK.
Most likely in the future you will buy or lease the car. But you will never buy the battery only lease it.
When the battery is fubar the manufacturer will recycle or resell for utility storage and replaces your battery pack.
Much like Auto companies went into Financing business to boost sales they will likely go into Battery management businesses to boost sales.
I can't see another way for long term.
We are I estimate 7-10 years from when batteries become such small percentage of ev cost to not matter. When you add 10% cost decline for solar electricity every year I think a lot of ice enthusiasts, politicians and car manufacturers haven't realised the hammer that is coming for them.
The cars purchased on that lease model were punished in their resale values in the Uk, to the point that Nissan discontinued the program.
For me, as a used car buyer who wants to buy a car outright (not on finance) that rules it out. I don't want to commit to paying Renault monthly to lease a battery at a price that is more than I currently spend on petrol.
To be fair, that is not very logical on my part, it does not make financial sense for me to go electric as I do so few miles.
The longer they can charge you with the same battery the more money they make.
Kinda like iPhones and their battery level when you get AppleCare. If it drops below 80% in the first 2 years you get a new one for free.
Also, people keep talking about converting batteries to home energy storage but its not that simple to do on your own - in fact its borderline dangerous to do so on your own due to hundreds tricky mistakes you can make that will end up with fire completely burning your home. This will only make sense at industrial scale but that also means it wont be too cheap anymore (not to mention those 8-years old cars which are in good condition, just missing battery that is more expensive than new car).
Also, I do think people are scared way too much by those dying batteries. Some of them will fails, sure, but there are so many gasoline cars with engines which have like 50% failire rate between 90k-180k miles driven. That's also pretty expensive to fix where often the only choice is to buy another engine from crashed car. I assume it might be similar here - 20-30% batteries will fail soon after the 8y warranty and will be replaced by batteries from crashed cars, the rest will work just fine for 15+y
I own Mach-E EV and I am scared. It's a great car, I love it but looking at what tesla is doing to the EV market - both new and used - I can't even fantom how it will look in a few years.