> They did it silently so users would upgrade rather than replace the battery.

That's a deliberately uncharitable interpretation. It could just as easily be explained by them wanting the customers to not have a crashing phone tarnishing their opinion of the brand. If it were about money, they should have popped up a message saying "The phone is going to be slower because the battery is dead, contact your Apple Store to buy a new battery."

It was not and still is not commonplace for any company to discuss the deep engineering details of a product's battery management logic with customers. The majority of products just stop working, some have an indicator of "bad battery".

Apple has a long record of making decisions for users without presenting options about them. Having these problems solved for us rather than being bothered with them is part of what we've paid for all these years. But their audience is broader now, they're much more successful, and when this practice rubs people the wrong way we all hear about it in the press as if it's some Antennagate-level flaw or scandal with which they were "caught." So they put in an option to make the phone worse but the user happier and move on. I would say "but the reputation damage is done" if it wasn't a foregone conclusion to so many that Apple must be up to no good.