The economics are pretty straightforward: What do you need to earn per day to make a living, including overhead? And how many widgets can you fix in a day? Here you are in the sticks. Let's say you need to make $1000 a month to cover your shop and $3000 a month to cover your life and family. You need to make a thousand a week or $200 a day or $25 an hour. Can you fix hair clippers in half an hour? Can you charge someone $12.50 to do it? A bitchin' $75 Wahl, maybe. A $20 Norelco, probably not. I dunno if the iPhone battery/screen repair shops have sprouted like mushrooms where you are but around here, there are plenty of people willing to do it for less than Apple. But then, Apple probably pays $80/sf for retail around here. We needed our Kitchenaid rebuilt. It cost $70. But then, it's a $300 kitchenaid. Amazon gives me 110 results for "stand mixers" under $70.
That's one of the complaints I have against sealed phones. I shouldn't have to pay someone money just to do a battery swap. It's a battery. Provided the device is designed right, there's pretty much zero ways to screw that up. I actually know of one place in town that does phone repairs. I keep on meaning to give them a call. I have a tablet sitting in my desk drawer right now that's only not working because it suffered the death wiggles (aka fucked up charging port). I keep on meaning to see if I can get it fixed, if even just so I can get the hard drive wiped and recycle the thing (but if I can get Android to update on it, it might be worth keeping). I wonder how the sub $70 stand mixers compare to your kitchenaid.
I want to agree but I've let the smoke out of a couple cheap eBay iPods doing the battery change. There's a difference between a non-serviceable component connected directly to the board and a user-swappable accessory. Making the battery swappable makes it marginally more expensive but it also complicates the design and "complication" = "bulk." I will bet you there's a surface-mount connector on the board that is proprietary and not available to strip-mall fixit shops.