I used to be the biggest Mac fanboy. From the orignal Macintosh in 1985 up through the mid 2000s. My last Mac was a Macbook Pro Aluminum - with an external battery.
Early in my engineering career I worked for a group that made battery packs and chargers for a variety of devices. I know a lot about rechargable batteries, and I wrote the firmware for battery chargers in addition to designing circuitry in chargers.
Batteries go bad over time. There is no known battery technology that avoids aging where a battery retains its original capacity and original self-impedance. Over time capacity decreases and impedance increases. It's the result of the migration of ions back and forth through the separator between the electrodes. There are some very expensive battery technologies that last a long time, like those used in satellites, or the Voyager spacecraft. But they all degrade over time.
When Apple stopped using external battery packs and put only embedded the batteries in their laptops, that was a deal breaker for me. I knew batteries would go bad, and it seemed like a crass move for planned obsolesence to me.
When it was found out that iPhones were intentionally throttling data to deal with old batteries, that made perfect sense to me. Higher data rates require more transmit current, and given that battery impedance increases over time, more current causes more voltage drop out of the battery, which can cause the phone to crash. I don't think they wanted to throttle data, but they had to reduce current draw in older phones because user's could not simply buy a new battery.
I have a Samsung phone; I recently replaced the battery because I noticed it wasn't lasting as long on a full charge. The new battery cost me $13. It works every bit as good as the original battery did when it was new.
I switched over to Windows about the time Windows 7 came out, and have not looked back. Two of my laptops (I mean my family) have had their original (external) batteries go bad. I bought new ones. They weren't as cheap as my cell phone replacement battery, but it wasn't a ridiculous cost.
I will never buy a phone or laptop with an embedded battery.