If anything, shipping and sitting on the previous incarnation of Siri as a basic feature set to shut up iPhone users for a few years while everything else matured might be viewed as a very shrewd move ten years from now.
That's one way of looking at it. Alternatively; Apple had their pick of the litter at TSMC for half a decade, and Nvidia beat them to 5 trillion total valuation with their design chops alone.
There comes a point at which these execs cannot have more yachts. Apple still wields far more societal influence than Nvidia does, and will for a long time to come; and of course there's nothing stopping them from forming a partnership and putting Nvidia chips into an Apple device if it came down to it.