The Tesla Model S has been out for almost 13 years, so you can already see it.
Your phone doesn't have liquid cooling temp management and is probably recharged daily. With a car that has 300 miles range, a lot of people probably only do a full cycle every week.
So 7000 to 8000 euros to replace a battery of a 80 to 100k car?
It depends on how many miles it has driven and how much other maintenance the car has had. It's a big expense but a battery dying is probably comparable to a timing belt breaking, those aren't cheap either and thats not even for luxury cars...
We had a 2010 Ford Transit van (diesel) and after 189000km, we sold it because the parts were becoming too hard to source (disclaimer: in New Zealand).
13 years old dead luxury cars are worthless, yes, especially when the tech is quickly evolving. That doesn't say anything about how long it takes for them to die or how reliable the tech is.
no car you can buy with this longevity tech, no phone either- same issue.