The key thing being that they apparently had a fallback plan, which I assume is always the case for every generation of iPhone. That means that while it might be unprecedented, it apparently wasn't unanticipated.
It wasn't clear from the article that there was a fallback plan, or that they decided to use a lightly modified previous gen GPU because that was the only way to get working silicon in the timeframe?
I suppose you’re right, although I find it hard to believe that wasn’t the explicit backup plan long before they even started investigating the new stuff that ended up not working out.
