Batteries don't "die", they degrade. You use lithium batteries in your phone every day. Does your phone just go from lasting a full day in a charge to not working overnight? No. Over the years it holds less and less charge. My last phone lasted 6 years before it went from lasting 2 full days until at the end of would only last about 16 hours. Phones charge to 100% and discharge to 0%, which kills lithium cells fast. If I had limited my phone to 90% charge and 10% discharge it would have lasted twice as long. If I had limited it to 80% and 20% it would have lasted 4 times as long. That's what most cars do. After 6 years, a car with the same lithium battery chemistry as my phone would still have about 88% of its original capacity. If the car went 300 miles on day 1, it would still be going 264 miles 6 years later. That's what the article is trying to explain to you, and that's precisely what is seen in real world tracking off EVs.