The leafs are fine cars but you're paying for being an early adopter. I bought one used in 2016, used it as a daily commuter till 2025 and then sold it. I don't think any car will ever be as cheap to run as that one....
My VW hybrid is just over 10 years. The advertising claimed 28 miles on a charge, but the reality was about 18 maximum, with stop-start somewhat less. After a couple of months when it had calibrated, it settled displaying 21 miles for a full charge. 10 years on, and it still reads 21 miles on a full charge, but the reading is less useful in use. It's common for it to drop from 21 to 15 miles after a mile, but to stay on 1 mile remaining for around 4 miles travelled. But essentially, I don't consider the range to have deteriorated too significantly, it still feels around the same ballpark.
A lot of the original thinking about batteries comes from the Nissan Leaf, introduced in 2009, when they guessed that batteries would probably need replacing after 10 years. However, from the cars that were written off from accidents, they discovered much less battery wear than predicted, and around the time I bought my car, they were suggesting batteries would be around 80% after 10 years and most manufacturers started using that figure. I'm not sure what current estimates are, but I wouldn't be surprised if it was closer to 90% after 10 years.
It's common knowledge amongst owners that range is significantly reduced in cold weather - I'd guess from my use, maybe 20% less range on a cold winter day compared to summer.
And as to why car batteries last so much longer than e.g. phone batteries, I think it's mostly because their charging limits are much more pessimistic. Typically a car charger won't ever charge beyond 90% capacity or discharge below 10%, and this is built into its estimated range (so 0 miles remaining is 10% charge).
Bigger issue is that it's been out of OEM updates for 3 years now, which is complete balls considering it's a reputable brand and came with "Android Enterprise Recommended" or whatever that was.
Of course they can.
How do you think they get the MTBF for hard drives?
What they do is deploy thousands of them and wait for the first one to fail. Then they wait for the second and third ones to fail… And then they can construct a statistical abstraction for the entire population based on the very first degradations … and that doesn’t take long at all.
A machine that presses a keyboard switch 500 times a second for several days straight is obviously not indicative of someone actually using the keyboard. But it'll get the "absolutely beat the snot out of it" number, which is usually good enough for marketing.
They build a test rig with 10,000 drives which they run continuously producing a total "drive hours" count and then wait for the first one or two or ten drives to fail.
X failures / 10,000,000 drive-hours will give you your MTBF, etc. ... and only takes ~40 days given a 10k drive test rig.
Some pictures from Seagate lab in Longmont:
https://cdn.mos.cms.futurecdn.net/yHqDagRDz9H5koWBefi24K-120...
https://cdn.mos.cms.futurecdn.net/EiZ9tA6p3UbaJFTaW75JdN.jpg
Because, otherwise, they would need to run those drives for years and years with reasonable cycling and read/write pressure to report accurate numbers based on real world failure rates in real conditions.