I’ve been tracking this.

The rough numbers I’ve seen from looking locally is the smaller cheaper ones tend to end their 8 year cycle with batteries worse off than advertised. Tesla included.

The more expensive ones sold back then seem to be ticking over as expected or in some cases slightly better than expected. The first Bmwi for example.

But the issue is that the volumes back then were far lower than what they are now. So data will be skewed based on customer type - do cheaper ones buy the car and do way more KMS / charge then more aggressively, vs expensive EV owners taking better care of the battery (using super fast less) and or doing less Kms?

We will see car manufacturing companies start to take notice of how their cars do and either advertise theirs are doing better than expected (while engineering the battery to be worse in the future to save money), or adjusting their warranty so they don’t get caught with the shittier battery replacements.