While I like your argument, making Cook solely responsible for this is a bit too much. He has been COO, mainly in production, he is not a software guy neither he is a genius like Jobs (no one is). So why all those bright and smart vice presidents at Apple failed to advice Cook on AI or why they *who are running iOS and MacOS divisions, actually failed themselves to improve Siri and lead in AI?
Sure, but ultimately it's the CEO's job to set a vision for the company, to choose his senior executives and to take or decline their advice and points of view. Tim Cook has been a fantastic company manager but he is not the COO anymore, he's the CEO, responsible for planning the roadmap of the company. It's
not his senior executives' role to decide the future of the company, only to provide their opinion and expertise to the CEO. If the CEO picked the wrong VPs or took the wrong advice, that's on him.
Apple under Steve Jobs was organized in a non-conventional way. The CEO (Steve) was very hands on, but it's that micromanaging and that vision from the very top that got Apple to stratospheric levels. When Steve was fired in the 90s, the company lost its way. It got back on track when Jobs was hired back. That wasn't a coincidence.
Apple can only go so far on Steve's old roadmap. If they miss something as big as AI, what else are they missing? Is the next "Apple" being developed in someone's garage and is Apple going to end up being IBM and Hewlett Packard? Tim Cook either has to surround himself by visionaries or he has to be replaced by one.