If their cloud service is an "ownership" model rather than a subscription access model like rd.io or Netflix they won't be getting much cash from me.
Android has been a mess for media and is only now starting to offer regular consumers the things they've had for years with iOS (movies, tv shows, netflix).
I'd guess Gruber's two overexcited paragraphs were the result of his trying to reconcile the "big deal" atmosphere surrounding WWDC (e.g. inviting world media) with what little he knows about it. It goes without saying that OTA sync is not the "game changer" Apple is ready to unleash on the world. If Apple's got a real game changer (and jury is still out) they're prolly going after markets worth over $100 billion.
The smartphone was a powerful disruptive device primarily because it converged the function of many things (among others "an ipod, a phone, an internet device" as Steve repeated at the debut). Tablets also did the same thing a bit less obviously.
Currently Apple offers 4 non-mobile consumer devices: computers (mac mini and iMac), Apple TV, Air Port and Time Capsule. In addition consumers also have televisions, game consoles, DVD/Blue Ray players, and stereos.
So my theory again is that Apple is coming out with a converged device that replaces* most of the above (I don't think they will sell the actual tvs or speakers).
* It won't replace them perfectly. In fact in many cases it will be strictly worse, as in the case of cloud gaming vs console gaming. But just as the best camera is the one you have with you, the totality of having one simple device that just works will be what they are banking on.
Call me a fan boy then. Many companies tried to make tablets before apple. The ipad was game changing. Many people tried to make mp3 players before apple. The ipod was game changing. Many people tried to make smart phones before apple. The iphone was game changing.
On that note, gmail + google docs + google apps were game changing. If apple can do as well or better, on their much superior platform, it will be game changing.