People willing to repair their own device is a niche audience as well. If you’re willing to go through the effort of fixing your device, there’s a decent chance you’re willing to flash a custom rom.
Or at least changing batteries used to be mainstream. Anyone born before the year 2000 should not be at all intimidated by changing a battery. I can't speak for Gen Z, it's possible they've lost that skill.
I remember having spare batteries for my Motorola, and an external battery charger, because charging via the built in would take ages.
Not going to these were the early ones. I think starting with the S8 or so they stopped letting you replace the battery. I'm on pixels now. And my Pixel 6 doesn't have a replaceable battery...
These days it’s a perilous task that requires multiple spudgers and picks, a screen heater, finger acrobatics to make sure you don’t slash or rip any fragile cables, and then you have to wrestle the battery from its adhesive coffin.