$79 is quite a bit of money to pay each year, considering I can buy two batteries and a charger for my Android phone on Amazon for far less than that.
The last couple of revisions of phones aren't that much better than previous generations. This seems mainly due to Moore's law slowing down. Heck, Intel hasn't released a process shrink in 4 years. Apple and other vendors are going to have to start pulling even more of these planned obsolescence tricks if technology doesn't pick up soon.
Plus $79 for a new battery PLUS expert, warrantied installation is a good value. You're paying for a lot more than just a battery.
(FWIW, I've replaced the batteries in my iPhone 4 and 5 in the last year. It was much easier than I thought it would be. I still have an original launch-day iPhone. Maybe I'll see if I can still find a replacement battery for it.)
Support a small business and have someone else install it for you if you need a new battery. It won’t cost that much. If Samsung had stores they would charge you something near Apples price without question.
(I've mentioned iFixit lately; I'm just a happy repeat customer.)
I'll be more than willing to take my chances with a lot of parts on computers/phones/electronics/etc
But the power supply systems are one area I will not buy anything other than OEM or "top of the line" for.
I've fallen asleep with my phone in bed, I have it on a nightstand a foot away from my head most nights, it sits in my pocket for most of the day. That's not something I want to have even a 1% chance of failing when the failure mode is "burst into flames".
I always wonder how people use those vaping devices (especially cheap ones from ebay) without fear of them blowing up, energy density is crazy there.
Every month or so I hear of another person who's phone caught fire on their bed, or the whole galaxy note fiasco. While I agree with you that for the most part it's not a worry in devices from reputable manufacturers (like OEMs), but it is and will continue to be a problem for cheaper manufacturers, and suppliers who aren't afraid to lie about what's inside the package.
Why wouldn't your first thought be "Hey, maybe Apple doesn't make the best battery for the iphone"? You already know they make a flawed one, maybe someone else makes one that isn't flawed?