"I'm sure when Apple met to discuss remotely degrading iPhone performance the words "They'll never notice" were spoken. Companies that sell complex services and oversell resources love this combo of fuzzy, hard to measure, diffuse, naturally erratic behaviour, broad tolerance, mixed with vague customer expectations."
I suspect Apple would prefer their products to be reliable rather than erratic.
They quite deliberately decided to make them degraded (to prolong
battery life). And they were fined for it [1]. Nobody mentioned
erratic in that case.
Not just to prolong battery life, to prevent the device from overdrawing the battery and shutting down when it couldn't provide the same peak current as it could when new.
This was likely a compromise from that design decision.
Since the slowdown was based on battery health and not absolute age of the device it was (and is) still possible to replace the battery.
But “the market” (ugh) seems to have decided that it wants phones with integrated batteries, and touch screens, and no physical keyboard, that are too big to use with one hand.
I suspect Apple would prefer their products to be reliable rather than erratic.