TBH, I wouldn't call Siri a search company nor an AI company. They were (and still are, a decade later) mediocre at both.
It seems to be taking time for the impact to show, but his fingerprints are all over iOS 15 with on-device Siri, contextual awareness, Google Lens features, etc.
Apple knows it's in a worse position now but they're betting that it's the better position to be in for the long term.
Case in point, it has always been possible to use Siri to turn on Airplane Mode, but until iOS 15 it was not possible to use it to turn it off (which they included in a demo at WWDC this year to somewhat humorous effect if you were paying attention)