On the other hand, what this also says (to people who like awesome cloud services) is :: "Unfortunately this also means that our predictive keyboard, Siri, and other predictive services will never be that good."
I don't think this precludes Apple from ever building better predictive services. Tim Cook is specifically saying that Apple does not sell or give away your data to third-parties for advertising purposes. He is NOT saying that Apple would never ask permission to read your e-mail if it meant that they could offer a compelling Apple-created product and user experience as a result.
For example, with Apple Pay, Apple is technically using and storing my private information (my credit card data) to offer me a compelling service. They are not going to then figure out which credit card I own and/or how much I spend, and sell that info to banks so that they can target me with specific credit offers.
Apparently they will know total aggregate spending through Apple Pay since it's been reported that they get a cut. But that's completely different from, "Hey we noticed you just bought X, why don't you also buy Y, or maybe next time get a better price at store Z"... which is more like the Google approach, and my personal preference is to avoid such 'features' like the plague.
From that point, Apple is completely out of the payment equation. The tokenised data is used to generate a once-off payment authorisation with your bank when you pay for a product using Apple Pay.
But I agree with the point of your post: if Apple thought collecting data would result in a significantly better product, they would probably do it.