Anyone who describes active voltage and frequency scaling in order to keep the cpu from crashing as “vile shenanigans” outs themselves as a person without worthwhile opinions on the topic.
The problem is that a couple years down the line when the battery degrades, that feedback loop adjusts and as a result that performance significantly deviates from what it was originally with no obvious way for the user to understand why or tell whether it even actually happened or if they’re just misremembering what the original performance was.
The user can be in the loop in a read-only way. If the control system suddenly makes dramatic & unexpected changes (to accommodate degraded power or thermal performance) the user should be notified so they can rectify the solution (replace the battery in this case). Apple would rather gaslight them into believing their phone is working fine and was just always this slow and it might be time for an upgrade.
Crashing the phone instead of throttling is a bad design choice no matter the serviceability of the battery. I had (and professionally supported) devices in the 00s that did this, and they were not good. People didn’t happily replace their battery and move on with their day, like you might imagine. They made support calls because their phone was constantly crashing and they had no idea why. But they made those calls on their office phone because their cell phone crashed when they tried to call me!
It is normal for mass market products to intentionally remove or never include niche features so that they can better appeal to the broader target market.
If you want a niche product, you have to buy a niche product: https://www.samsung.com/us/business/mobile/phones/galaxy-xco...
Why isn't the Galaxy XCover Pro a top selling phone? It has a battery door! The answer is that few buyers care.
Except removable batteries were never a niche feature; most smartphones in the previous generation had removable batteries, and most smartphones today have it too, just glued instead to prevent users from removing them. Apple deliberately denied users that ability to ensure their reliance on its own repair services, and the rest of the industry followed with the same scammy tactic after seeing it getting tolerated by Apple's consumers.