Yup. You gotta take everything he says with a grain of salt. I vaguely remember arguing with him over larger phones, and he pulled out the old tried and true "average consumer doesn't care about phones over 4 inches" argument.
...and what do you know, the iPhone 6+ came out, and is making Apple a bundle, apparently breaking all kinds of sales records. The same thing happened with the iPad Mini, which I know quite a few people here dismissed with the same perfect size, average consumer argument.
That's not to say an iPad Pro will make just as many waves. It'll be more expensive, and by design caters to a much narrower niche. But if it's good, it'll sell, and Apple will make money.