I had an interesting experience yesterday with my wife's macbook air that is somewhat relevant to this discussion.
I made an appointment at the applestore for another issue (accidental screen damage to my iPad pro under AppleCare +) and since I was going to be there anyway I made on for my wife's 2013 MacBook air. I wanted to get the battery replace while apple repair was still available, so I could get a genuine battery.
Previously, I ran coconut battery app, it showed an 84% lifespan, and that the battery was a couple of weeks older than my purchase date.
The genius ran his diagnostics, it showed an 88% battery health. He then said that apple will not replace a battery (even with me paying the cost) unless is shows a failure/end of lifespan. I countered with what would happen when the computer became end of life (April) and the battery degraded a month afterward, I would be unable to get a genuine battery replacement and be stuck with an eBay chinese battery. I further pointed out if I brought an iPhone or mac to apple with one of those batteries, they would hand it back and refuse to service it, because they don't trust them not to explode, yet that is what they want me to use when they refuse to replace the battery 3 months from now and i then need a new one.
Anyway, going after a couple of rounds with this guy, he went to his manager and his manager had no issues with a battery replacement. After he came back and told me that apple would perform the battery replacement over his objections, but he said I wasn't being environmental because the battery is the most toxic part of the computer, so I should not preform the replacement just hope that the battery will last several more years.
(I played nice, but I wondered if apple just throws the toxic batteries into a barrel and lights it on fire out back, or if they recycle it which would capture and hazardous materials, something they can't guarantee a third party repair place would do. It should be more environmentally responsible to have apple take custody of the used battery for recycling, vs leaving consumers to the mercy of third party shops.)
(Oh, and he said a computer lasting 10 years isn't realistic anyway, despite not knowing or asking the tasks my wife uses it for.)
Anyway, I am now waiting for the part to arrive so I can get the battery service performed, but I didn't expect all the static I received with my request to replace an almost 6 year old battery with a fresh one at apple.
I may reach out to apple's executive relations team, after the repair is completed, although I doubt they will care much about what happened or how they should extend battery repairs on their computers to a more realistic lifespan.