Apple's own design guidelines originally said not to do the thing they did (and which they are now once again saying not to do).

Couldn't Apple have just, like, talked to the people who originally wrote the guidelines? Why do they need to re-invent the wheel? Will Apple forget again in another 15 years and need to re-run the experiment, taking us all along as test subjects?

Why do you assume they didn't talk to those people?

Decisions should be revisited when it makes sense to do so.