It isn't reported or announced because everyone would chalk it up as the car's that old.No auto manufacturer expects a car to explode when it’s old.
If this is a normal issue, Apple would be required to implement measures to ensure people don’t use their phones past a certain date.
In aviation we have a TBO or time before overhaul, to ensure safety; typically 2000 flight hours. If Apple thinks that people should not be using phones older than seven years, they should issue a warning with the product.
Other brands than Apple do experience flame up of devices when the battery's that worn or that old. As a safety measure battery bloat is a feature to force users to stop using it.
As these fires are so rare and the odds of its users are still using devices past their "vintage" or "obsolete"
then why the need for an active campaign?
This is unlike the aviation industry where in planes are used beyond half a century and seeming it can fall on top of people in ground a safety recall/announcement should be made.
But again... if the vehicle's older than half the world's population then it isn't really the responsibility of the manufacturer but of the owner/end user to make the call to retire it.
Again, that iPhone's more than a dozen year's old. I'd be alarmed if it occured to a device less than half that old.