What they should have done is include the toggle from day one, clearly explained why the feature was built, and then presented users with a prompt to enable it if the phone detected it may be necessary. Shoving it down peoples throats just made for terrible optics and "planned obsolescence" was a very well fitting and easy explanation in the absence of the real one that few understood.
Like, people still talk about it like it was a bad thing, see this thread for evidence, and this is one of the places where I would expect to find one of the largest concentrations of people that do understand what that patch did and why it was necessary.
Personally I think it's pretty great to know that I can use my iPhone even with a degraded battery and not have it shut down unexpectedly.
I've had both iPhones and Androids do that in the past, often in cold weather and during bursts of high load (like on a chairlift at a ski resort, which my example here is based on).
The idea was good, but it was implemented in a way that created issues for some users (eg: my iPhone 5 being sluggish all the time) and benefited Apple as most users would simply buy a new iPhone because no one knew what was going on.