NLU is very specialized AI with direct business impact, in that you can sell it as SaaS. All the cloud providers do this. Same with STT and TTS. MS wants Nuance’s tech in Azure and their IP to protect themselves against lawsuits.
In addition to this point, I think it’s also comparing apples (excuse the pun) to oranges. Apple does not make big acquisitions: they buy up companies that are still flying under the radar, early enough that they can dramatically steer the technology. It’s just not Apple’s style to buy an $18 billion company. Amazon and Google and Microsoft, sure. But if Cupertino bought a big AI company, that’s what would make me blink.